Amendment No. 1 to Schedule 13D

This Amendment No. 1 (“Amendment No. 1”) amends and supplements the Schedule 13D filed with the Securities and Exchange Commission (the “SEC”) on August 4, 2020 (the “Schedule 13D”). Except as specifically provided herein, this Amendment No. 1 does not modify any of the information previously reported in the Schedule 13D, as amended. Capitalized terms used herein shall have the meanings ascribed to them in the Schedule 13D.

Item 2 of the Schedule 13D is hereby amended and restated as follows:

This Schedule 13D is filed jointly by (i) Bpifrance Participations S.A., a société anonyme incorporated under the laws of the Republic of France (“Bpifrance Participations”), (ii) the Caisse des Dépôts, a French special public entity (établissement spécial) (“CDC”), (iii) EPIC Bpifrance, a French public institution of industrial and commercial nature (“EPIC”) and (iv) Bpifrance S.A., a société anonyme incorporated under the laws of the Republic of France. Bpifrance Participations, CDC, EPIC and Bpifrance S.A. are referred to herein collectively as the “Reporting Persons.” The principal address for CDC is 56, rue de Lille, 75007 Paris, France. The principal address for Bpifrance Participations, Bpifrance S.A. and EPIC is 27-31, avenue du Général Leclerc, 94710 Maisons-Alfort Cedex, France.

Bpifrance Participations is a French public investment entity specializing in the business of equity financing via direct investments or fund of funds. Bpifrance Participations is a subsidiary owned at 99.99% by Bpifrance S.A., a French credit institution. CDC and EPIC each hold 49.2% of the share capital of Bpifrance S.A. and jointly control Bpifrance S.A. CDC is principally engaged in the business of long-term investments. EPIC, a French public institution of industrial and commercial nature, is principally engaged in the business of banking finance.

Bpifrance S.A. may be deemed to be the beneficial owner of shares held by Bpifrance Participations, indirectly through its 99.99% ownership of Bpifrance Participations. CDC and EPIC may be deemed to be the beneficial owners of shares held by Bpifrance Participations, indirectly through their joint ownership and control of Bpifrance S.A.

Attached as Appendices A, B, C and D to Item 2 is information concerning the executive officers and directors of Bpifrance Participations, CDC, EPIC and Bpifrance S.A., respectively, required to be disclosed in response to Item 2 and General Instruction C to Schedule 13D.

None of the Reporting Persons, nor, to the best of their knowledge, any of the persons referred to in Appendices A, B, C and D to Item 2 has, during the last five years, been convicted in a criminal proceeding (excluding traffic violations and similar misdemeanors) or been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree, or final order enjoining future violations of, or prohibiting or mandating activities subject to, Federal or state securities laws or finding any violation with respect to such laws.

Item 5(c) of the Schedule 13D is hereby amended and supplemented as follows:

CDC Croissance S.A., a wholly-owned subsidiary of CDC, purchased Ordinary Shares of Cellectis S.A. on the following date at the daily average price indicated below. As a result of this transaction, CDC Croissance S.A. holds 275,100 shares of Cellectis S.A. CDC may be deemed to be the beneficial owner of the shares held directly by Croissance S.A., indirectly through its ownership of CDC Croissance S.A.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

APPENDIX A

Name, business address, present principal occupation or employment and place of citizenship of the directors and executive officers of

BPIFRANCE PARTICIPATIONS S.A.

The name, business address and present principal occupation or employment of each of the directors and executive officers of Bpifrance Participations S.A. are set forth below. The business address of each director and executive officer is Bpifrance Participations S.A., 27-31, avenue du Général Leclerc, 94710 Maisons-Alfort Cedex, France. Unless otherwise indicated, each director and executive officer is a citizen of France.

BOARD OF DIRECTORS

EXECUTIVE OFFICERS

APPENDIX B

Name, business address, present principal occupation or employment and place of citizenship of the directors and executive officers of

CAISSE DES DÉPÔTS

The name, business address and present principal occupation or employment of each of the members of the Management Committee of Caisse des Dépôts are set forth below. The business address of each director and executive officer is Caisse des Dépôts, c/o 56, rue de Lille, 75007 Paris, France. Unless otherwise indicated, each such person is a citizen of France.

MANAGEMENT COMMITTEE

APPENDIX C

Name, business address, present principal occupation or employment and place of citizenship of the directors and executive officers of

EPIC BPIFRANCE

The name, business address and present principal occupation or employment of each of the directors and executive officers of EPIC Bpifrance are set forth below. The business address of each director and executive officer is EPIC Bpifrance, 27-31, avenue du Général Leclerc, 94710 Maisons-Alfort Cedex, France. Unless otherwise indicated, each director and executive officer is a citizen of France.

DIRECTORS

APPENDIX D

Name, business address, present principal occupation or employment and place of citizenship of the directors and executive officers of

BPIFRANCE S.A.

The name, business address and present principal occupation or employment of each of the directors and executive officers of Bpifrance S.A. are set forth below. The business address of each director and executive officer is Bpifrance S.A., 27-31, avenue du Général Leclerc, 94710 Maisons-Alfort Cedex, France. Unless otherwise indicated, each director and executive officer is a citizen of France.

DIRECTORS