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 June 2018

CGG

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

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 ☐

~~Form 20-F ☒ Form~~CGG ~~40-F ☐~~Delivers Final PSTM Products for Dunquin

~~CGG Completes Mozambique~~ Multi-Client Survey in ~~Zambezi~~Ireland’s ~~Delta~~Porcupine Basin

Paris, France – June 1314, 2018

CGG has completed ~~acquisition~~the ofPre-Stack ~~15,400~~Time ~~km2~~Migration (PSTM) of 3Dits ~~marine~~2,500-sq-km ~~seismic~~Dunquin ~~data~~multi-client survey acquired in ~~the~~Block ~~outer~~44 ~~Zambezi~~of ~~Delta~~the Porcupine Basin, west of ~~the~~Ireland, ~~Beira~~in ~~High~~2017. ~~The~~Dunquin ~~survey~~is ~~area~~the ~~covers~~latest ~~blocks~~in Z5a series of multi-C client surveys that CGG has recently been acquiring in the area, totaling 10,500 sq km of 3D and Z5around 2,000 km of long-Doffset 2D broadband data. PSDM products for its 2016 Galway and ~~surrounding~~Cairenn ~~non-held~~surveys ~~acreage~~were delivered last year.

~~This~~Similar isto CGG’s Galway and Caireen surveys, the ~~first~~Dunquin ~~survey~~data towill be processed ~~conducted~~through ~~following~~advanced ~~the~~velocity ~~agreement~~modeling ~~CGG~~and ~~signed~~depth ~~with~~imaging, ~~Mozambique’s~~following ~~Instituto~~industry ~~Nacional~~funding. deInitial ~~Petroleo~~FWI ~~(INP)~~results in– ~~2017~~as ~~for~~illustrated in the ~~acquisition~~image below – reveal important details of athe ~~new~~carbonate ~~multi-client~~reservoir ~~program~~that forms the Dunquin structure.

~~The~~Luc ~~fast~~Schlumberger, EVP, Multi-~~track~~Client & ~~PreSTM~~New ~~data~~Ventures, ~~set~~CGG, ~~will~~said: be“Our ~~available~~new inDunquin Q4data ~~2018~~set inadds ~~anticipation~~to ofour ahigh-quality ~~licence~~coverage ~~round~~west ~~during~~of ~~2019~~Ireland, shedding ~~and~~new ~~final~~light ~~PreSDM~~on ~~deliverables~~the ~~will~~characteristics beof ~~made available~~known inand Q4undrilled ~~2019~~structures. AIt ~~JumpStart™ integrated geoscience package~~ will ~~complement~~enhance ~~the survey to help accelerate~~ industry understanding of ~~the~~potential ~~petroleum~~areas ~~systems~~of interest in ~~the~~this ~~area~~still unexplored region.”

LOGO

AsA ~~part~~preliminary ofFWI ~~CGG’s~~test ~~commitment~~reveals togeologic ~~sustainability~~details ~~and high environmental standards, Sercel’s QuietSea™ advanced integrated passive acoustic monitoring system was deployed on the survey vessel to ensure best-in-class monitoring~~ of ~~marine~~a ~~mammals~~buried involcanic ~~the~~island ~~environmentally~~and ~~sensitive~~coral ~~Mozambique~~reef ~~Channel.~~atoll

~~Sophie~~(image ~~Zurquiyah,~~courtesy ~~CEO,~~of CGG, ~~said:~~Multi-Client & “This advanced 3D survey is being imaged with our latest subsurface imaging technologies. Combined with our JumpStart integrated geoscience program, regional coverage from our 2017 East Africa Robertson Study, and the Robertson New Ventures ~~Suite, it will support INP’s promotion of the potential in the deepwater Zambezi Delta Basin and the west flank of the Beira High~~). This full package will also provide interested industry companies with the information required to confidently de-risk the full Paleozoic, Mesozoic and Cenozoic series in this exciting new exploration area.”

Map showing location of CGG’s recently completed 3D survey over the Beira High in the Zambezi Delta.

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 businesses of Equipment, Acquisition and Geology, Geophysics & Reservoir (GGR), CGG brings value across all aspects of natural resource exploration and exploitation. CGG employs more than 5,300 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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Contacts

Group Communications

Christophe Barnini

Tel: + 33 1 64 47 38 11

E-Mail: : invrelparis@cgg.com

Investor Relations

Catherine Leveau

Tel: +33 1 64 47 34 89

E-mail: : invrelparis@cgg.com

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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.

SIGNATURES

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

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Date June 13th, 2018

/s/ Yves Goulard

Date June 14th, 2018

/s/ Yves Goulard

Y. GOULARD

Group Treasurer, acting Chief Financial Officer

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