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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 of
the Securities Exchange Act of 1934

Date of Report: April 10, 2018
Commission File Number: 001-36891

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 ⃞

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): ⃞

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): ⃞

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EXHIBIT INDEX

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.

3

Exhibit 99.1

Cellectis Announces Closing of Follow-On Offering

NEW YORK--(BUSINESS WIRE)--April 10, 2018--Regulatory News:

Cellectis S.A. (Paris:ALCLS) (NASDAQ:CLLS) (NASDAQ: CLLS – EURONEXT GROWTH: ALCLS), a clinical-stage biopharmaceutical company focused on developing immunotherapies based on gene-edited allogeneic CAR T-cells, today announced the closing of its underwritten offering of 5,646,000 American Depositary Shares (“ADS”) at a public offering price of $31.00 per ADS. The net proceeds to Cellectis from the offering are approximately $163.7 million, after deducting the estimated expenses related to the offering and the underwriting discounts and commissions payable by Cellectis. In connection with the offering, Cellectis granted the underwriters a 30-day option to purchase up to an additional 846,900 ADSs. The ADSs are listed on the Nasdaq Global Market under the symbol “CLLS” and Cellectis’ ordinary shares are listed on the Euronext Growth market of Euronext in Paris under the symbol “ALCLS”.

Goldman Sachs & Co. LLC, Citigroup and Barclays acted as book-running managers for the offering. Nomura acted as lead manager and Oppenheimer & Co. and Ladenburg Thalmann acted as co-managers.

A shelf registration statement on Form F-3 (including a prospectus) relating to Cellectis’ American Depositary Shares was filed with the Securities and Exchange Commission (the “SEC”) and has become effective. A copy of the prospectus supplement (and accompanying prospectus) relating to the offering may be obtained from Goldman Sachs & Co. LLC, Attention: Prospectus Department, 200 West Street, New York, NY 10282, or by telephone at (866) 471-2526 or by email at prospectus-ny@ny.email.gs.com, Citigroup Global Markets Inc., c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, NY 11717, or by telephone at (800) 831-9146 or Barclays Capital Inc., c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, New York 11717, or by telephone at (888) 603-5847 or by email at barclaysprospectus@broadridge.com.

This press release shall not constitute an offer to sell or the solicitation of an offer to buy these securities, nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction. In particular, no public offering of the ADSs will be made in Europe.

Special Note Regarding Forward-Looking Statements

This press release contains “forward-looking” statements that are based on our management’s current expectations and assumptions and on information currently available to management. Forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. Further information on the risk factors that may affect company business and financial performance is included in Cellectis’ Annual Report on Form 20-F for the year ended December 31, 2017, and subsequent filings Cellectis makes with the SEC from time to time. Except as required by law, we assume no obligation to update these forward-looking statements publicly, or to update the reasons actual results could differ materially from those anticipated in the forward-looking statements, even if new information becomes available in the future.

CONTACT:
For further information, please contact:
Media contacts
Cellectis S.A.
Jennifer Moore, 917-580-1088
VP of Communications
media@cellectis.com
or
KCSA Strategic Communications
Caitlin Kasunich, 212-896-1241
ckasunich@kcsa.com
or
Investor Relations contact
Cellectis S.A.
Simon Harnest, 646-385-9008
VP of Corporate Strategy and Finance
simon.harnest@cellectis.com