[6-K] Cellectis S.A. Current Report (Foreign Issuer)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

Report of Foreign Private Issuer

Pursuant to Rule 13a-16 or 15d-16

under the Securities Exchange Act of 1934

Date of Report: November 7, 2025

Commission File Number: 001-36891

Cellectis S.A.

(Exact Name of registrant as specified in its charter)

8, rue de la Croix Jarry

75013 Paris, France

+33 1 81 69 16 00

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

Form 20-F ☒ Form 40-F ☐

Cellectis S.A.

The information included in this report on Form 6-K, including Exhibit 99.1, shall be deemed to be incorporated by reference in the registration statements of Cellectis S.A. on Form F-3 (Nos. 333-284302 and 333-288491) and Form S-8 (Nos. 333-204205, 333-214884, 333-222482, 333-227717, 333-258514, 333-267760, 333-273777, 333-284301 and 333-290218), to the extent not superseded by documents or reports subsequently filed.

EXHIBIT INDEX

Exhibit		Title
99.1		Cellectis S.A.’s interim report for the nine-month period ended September 30, 2025.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

	CELLECTIS S.A. (Registrant)
November 7, 2025	By:	/s/ André Choulika
		André Choulika
		Chief Executive Officer

FAQ

What did Cellectis (CLLS) file?

A Form 6-K furnishing its interim report as Exhibit 99.1.

What period does Cellectis’s interim report cover?

The interim report covers the nine-month period ended September 30, 2025.

What is included as Exhibit 99.1 in the 6-K?

Cellectis S.A.’s interim report for the nine-month period ended September 30, 2025.

Are the 6-K materials incorporated by reference?

Yes. The information, including Exhibit 99.1, is incorporated by reference into Form F-3 and Form S-8 registration statements.

Which registration statement forms are referenced?

Form F-3 and Form S-8 registration statements are referenced for incorporation by reference.

Does the filing list the company’s principal executive office?

Yes. It lists 8, rue de la Croix Jarry, 75013 Paris, France with phone +33 1 81 69 16 00.