The review began in February after Egg's takeover of French online firm Zebank (PRWeek, 8 February).
Egg corporate comms head Emma Byrne said GCI is tasked with building corporate and brand awareness and providing some lobbying work.
The agency will also handle PR surrounding the launch of an as-yet-unannounced product in France this summer.
'It's about establishing Egg as a brand in France because, at the moment, we don't have a product there,' said Byrne.
Egg previously used Euro RSCG for local media relations surrounding the Zebank acquisition.