This is not a surprise, CGG is a French company (do not forget the strong Union in France).
Google translate recommended:
http://www.lemarin.fr/secteurs-activites/shipping/27188-cgg-le-geo-coral-quitte-la-france-la-cfdt-obtient-une-table-ronde
3 replies (most recent on top)
They will move as much as possible to France (they started a long time ago, about 2 years).
back office and support staff could easily be moved, the rest not so much IMO.