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

For the month of November 2017

CGG

Tour Maine Montparnasse - 33 Avenue du Maine – BP 191 - 75755 PARIS CEDEX 15

(address of principal executive offices)

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

Form 20-F  ☒    Form 40-F  ☐

Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

Yes  ☐    No  ☒

If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): 82                 

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Trading halt request for

December 1, 2017 starting 2pm

Paris, France – November 30, 2017

The decision by the Commercial Court of Paris on the approval of the draft safeguard plan and on the claim filed against it by certain holders of convertible bonds is expected in the afternoon of December 1, 2017. Therefore, the Company will ask for a trading halt on the Company’s shares (ISIN : FR 0013181864), convertible bonds due 2019 (ISIN : FR 0011357664) and convertible bonds due 2020 (ISIN : FR 0012739548) on Euronext Paris and CGG’s American Depository Shares (symbol “CGG”) on the New York Stock Exchange from Friday December  1, 2017 at 2:00pm (CET), until the close of the French market.

About CGG

CGG ( www.cgg.com ) is a fully integrated Geoscience company providing leading geological, geophysical and reservoir capabilities to its broad base of customers primarily from the global oil and gas industry. Through its three complementary business divisions of Equipment, Acquisition and Geology, Geophysics & Reservoir (GGR), CGG brings value across all aspects of natural resource exploration and exploitation. CGG employs around 5,400 people around the world, all with a Passion for Geoscience and working together to deliver the best solutions to its customers.

CGG is listed on the Euronext Paris SA (ISIN: 0013181864) and the New York Stock Exchange (in the form of American Depositary Shares. NYSE: CGG).

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THIS FORM 6-K REPORT IS HEREBY INCORPORATED BY REFERENCE INTO CGG’S REGISTRATION STATEMENT ON FORM S-8 (REGISTRATION STATEMENT NO. 333-150384, NO. 333-158684, NO. 333-166250, NO. 333-173638, NO. 333-188120 AND NO. 333-197785) AND SHALL BE A PART THEREOF FROM THE DATE ON WHICH THIS REPORT IS FURNISHED, TO THE EXTENT NOT SUPERSEDED BY DOCUMENTS OR REPORTS SUBSEQUENTLY FILED OR FURNISHED.