Exhibit 99.1

Constellium Reports Fourth Quarter and Full Year 2018 Results

Amsterdam – February  21, 2019 – Constellium N.V. (NYSE: CSTM) today reported results for the fourth quarter and full year ended December 31, 2018.

Fourth quarter 2018 highlights:

Shipments of 370 thousand metric tons, up 6% compared to Q4 2017

Revenue of € 1.4 billion, up 12% compared to Q4 2017

Net loss of € 57 million compared to net loss of € 80 million in Q4 2017

Adjusted EBITDA of € 104 million, up 1% compared to Q4 2017

Full year 2018 highlights:

Shipments of 1.5 million metric tons, up 3% compared to 2017

Revenue of € 5.7 billion, up 9% compared to 2017

Net income of € 190 million compared to net loss of € 31 million in 2017

Adjusted EBITDA of € 498 million, up 11% compared to 2017

Net debt / LTM Adjusted EBITDA of 4.0x compared to 4.2x at December 31, 2017

Project 2019 run-rate cost savings of € 43 million achieved as of December 31, 2018

Jean-Marc Germain, Constellium’s Chief Executive Officer said, “Constellium delivered strong results in 2018. Our Adjusted EBITDA of € 498 million increased by 11%, coming in well above our initial ‘high single digit’ guidance. Further, each of our three business units delivered record annual Adjusted EBITDA. We also made significant progress on strategic initiatives in 2018, notably the sale of the North Building at Sierre and the agreement to acquire our partner’s interest in our Bowling Green joint venture. Overall, I am proud of the achievements our team made during the year, and I am very optimistic about the prospects for our future.”

Mr. Germain continued, “We are maintaining our guidance of Adjusted EBITDA growth of 8% to 10% and Free Cash Flow in excess of € 50 million in 2019. Our focus is on delivering our long-term targets of Adjusted EBITDA over € 700 million and leverage of 2.5x in 2022. We are committed to increasing value for our shareholders through the execution of our strategy.”

Group Summary

The difference between the sum of reported segment revenue and total group revenue includes revenue from certain non-core activities and inter-segment eliminations. The difference between the sum of reported segment Adjusted EBITDA and the Group Adjusted EBITDA is related to Holdings and Corporate.

For the fourth quarter of 2018, shipments of 370 thousand metric tons increased 6% compared to the fourth quarter of last year due to higher shipments in each of our segments. Revenue of € 1.4 billion increased 12% compared to the fourth quarter of last year primarily due to higher shipments and improved price and mix. Net loss of € 57 million improved compared to a net loss of € 80 million in the fourth quarter of 2017 due largely to costs related to the refinancing completed in the fourth quarter of 2017. Adjusted EBITDA of € 104 million increased 1% from the fourth quarter of last year primarily due to improved results in the Packaging and Automotive Rolled Products segment, partially offset by weaker results in the Automotive Structures and Industry segment.

For the full year of 2018, shipments of 1.5 million metric tons increased 3% compared to last year on higher shipments in each of our segments. Revenue of € 5.7 billion increased 9% compared to last year primarily due to higher shipments, higher aluminium prices and improved price and mix. Net income of € 190 million improved compared to a net loss of € 31 million in 2017 largely due to the gain on the sale of the North Building at Sierre in 2018. Adjusted EBITDA of € 498 million increased 11% compared to last year on improved results in each of our three business segments.

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Results by Segment

Packaging & Automotive Rolled Products (P&ARP)

Fourth quarter Adjusted EBITDA increased compared to the fourth quarter of 2017 as increased shipments, favorable metal costs and solid cost control were partially offset by weaker price and mix and incremental costs from maintenance and the ramp up of our automotive programs.

For the fourth quarter of 2018, shipments of 254 thousand metric tons increased 6% from the fourth quarter of last year due to higher shipments of both Packaging rolled products and Automotive rolled products. Revenue of € 737 million increased 11% compared to the fourth quarter of 2017 primarily due to higher shipments.

For the full year of 2018, Adjusted EBITDA of € 243 million increased compared to last year primarily due to higher volumes, improved price and mix, favorable metal costs and solid cost control, partially offset by incremental costs from maintenance and the ramp up of our automotive programs. Shipments of 1.0 million metric tons increased 3% compared to the last year as higher Automotive rolled product shipments were partially offset by lower Packaging rolled product shipments. Revenue of € 3.1 billion increased 9% compared to last year primarily due to higher aluminium prices and higher shipments.

Aerospace & Transportation (A&T)

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Fourth quarter Adjusted EBITDA increased slightly compared to the fourth quarter of 2017 due to higher shipments on solid operational performance, partially offset by weaker price and mix and slightly higher costs.

For the fourth quarter of 2018, shipments of 59 thousand metric tons increased 7% compared to the fourth quarter of last year on higher shipments of both Aerospace rolled products and Transportation, Industry and Other rolled products. Revenue of € 349 million increased 9% compared to the fourth quarter of 2017 primarily due to higher volumes.

For the full year of 2018, Adjusted EBITDA of € 152 million increased 4% compared to last year on higher shipments and solid cost control, partially offset by weaker price and mix. Shipments of 246 thousand metric tons increased 3% compared to last year on higher shipments of both Aerospace rolled products and Transportation, Industry and Other rolled products. Revenue of € 1.4 billion increased 4% compared to last year as higher shipments and higher aluminium prices were partially offset by foreign exchange translation.

Automotive Structures & Industry (AS&I)

Fourth quarter Adjusted EBITDA decreased compared to the fourth quarter of 2017 primarily due to higher costs largely related to maintenance, new product launches and our footprint expansion.

For the fourth quarter of 2018, shipments of 57 thousand metric tons increased 1% compared to the fourth quarter of last year on higher Other extruded product shipments. Revenue of € 324 million increased 18% compared to the fourth quarter of 2017 primarily due to improved price and mix.

For the full year of 2018, Adjusted EBITDA of € 125 million increased 4% compared to last year on higher shipments and improved price and mix partially offset by higher costs. Shipments of 249 thousand metric tons increased 6% compared to last year due to higher shipments of both Automotive extruded products and Other extruded products. Revenue of € 1.3 billion increased 15% compared to last year on higher shipments and improved price and mix.

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Net Income

For the fourth quarter of 2018, net loss of € 57 million compared to a net loss of € 80 million in the fourth quarter of last year. The change in net income is primarily attributable to lower financing costs compared to the same period of 2017, which included the costs of the refinancing completed in that period, and lower income tax expense compared to the same period of 2017 as a result of the U.S. Tax Cuts and Jobs Act of 2017, partially offset by an unfavorable change in the value of unrealized derivatives and an unfavorable effect from metal lag.

For the full year of 2018, net income of € 190 million compared to a net loss of € 31 million in the prior year. The change in net income is primarily attributable to a gain from the sale of the North Building at Sierre, lower financing costs, the improvement in Adjusted EBITDA and lower income tax expense, partially offset by an unfavorable change in the value of unrealized derivatives.

Cash Flow and Liquidity

Free Cash Flow was an outflow of € 225 million for the full year of 2018 compared to an outflow of € 134 million in the prior year. The change was primarily due to higher working capital, partially offset by higher Adjusted EBITDA and lower interest expense.

Cash flows from operating activities were € 66 million for the full year of 2018 compared to cash flows from operating activities of € 160 million in the prior year. Constellium reduced factored receivables by € 27 million in 2018 compared to a decrease of € 93 million in the prior year.

Cash flows used in investing activities were € 91 million for full year of 2018 compared to cash flows used in investing activities of € 292 million in the prior year. Cash flows used in investing activities included € 198 million of proceeds from disposals net of cash related to the sale of the North Building at Sierre in 2018.

Cash flows used in financing activities were € 82 million for the full year of 2018 compared to cash flows from financing activities of € 61 million in the prior year.

Liquidity at December 31, 2018 was € 669 million, comprised of € 164 million of cash and cash equivalents and € 505 million available under our committed lending facilities and factoring arrangements. Liquidity at December 31, 2017 was € 531 million.

Net debt was € 1,996 million at December 31, 2018 compared to € 1,889 million at December 31, 2017.

Outlook

We expect Adjusted EBITDA growth in a range of 8% to 10% in 2019 and expect over € 700 million of Adjusted EBITDA in 2022. This guidance reflects the effect of the application of IFRS 16 and the consolidation of Bowling Green, both beginning in Q1 2019.

We are not able to provide a reconciliation of this Adjusted EBITDA guidance to net income, the comparable GAAP measure, because certain items that are excluded from Adjusted EBITDA cannot be reasonably predicted or are not in our control. In particular, we are unable to forecast the timing or magnitude of realized and unrealized gains and losses on derivative instruments, metal lag,

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impairment or restructuring charges, or taxes without unreasonable efforts, and these items could significantly impact, either individually or in the aggregate, net income in the future.

Recent Developments

On January 10, 2019, Constellium completed the purchase of Tri-Arrows Aluminum Holding Inc.’s 49% stake in Constellium-UACJ ABS, LLC for $100 million plus the assumption of 49% of approximately $80 million of third party debt at Constellium-UACJ ABS, LLC.

Forward-looking statements

Certain statements contained in this press release may constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. This press release may contain “forward-looking statements” with respect to our business, results of operations and financial condition, and our expectations or beliefs concerning future events and conditions. You can identify forward-looking statements because they contain words such as, but not limited to, “believes,” “expects,” “may,” “should,” “approximately,” “anticipates,” “estimates,” “intends,” “plans,” “targets,” likely,” “will,” “would,” “could” and similar expressions (or the negative of these terminologies or expressions). All forward-looking statements involve risks and uncertainties. Many risks and uncertainties are inherent in our industry and markets. Others are more specific to our business and operations. These risks and uncertainties include, but are not limited to, economic downturn, the loss of key customers, suppliers or other business relationships; disruption to business operations; the inability to meet customer quality requirements; delayed readiness for the North American Auto Body Sheet market, the capacity and effectiveness of our hedging policy activities, failure to retain key employees, and other risk factors set forth under the heading “Risk Factors” in our Annual Report on Form 20-F, and as described from time to time in subsequent reports filed with the U.S. Securities and Exchange Commission. The occurrence of the events described and the achievement of the expected results depend on many events, some or all of which are not predictable or within our control. Consequently, actual results may differ materially from the forward-looking statements contained in this press release. We undertake no obligation to update or revise any forward-looking statement as a result of new information, future events or otherwise, except as required by law.

About Constellium

Constellium (NYSE: CSTM) is a global sector leader that develops innovative, value added aluminium products for a broad scope of markets and applications, including aerospace, automotive and packaging. Constellium generated € 5.7 billion of revenue in 2018.

Constellium’s earnings materials for the fourth quarter and full year ended December 31, 2018, are also available on the company’s website ( www.constellium.com ).

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