The 27-year-old had been linked with a move to Rennes in recent weeks and has now put pen-to-paper on a three-year deal at the club.
Rivals Lens were also interested in Barbosa but failed to land the player, who may well join Fulham's Abdeslam Ouaddou (pictured) at Rennes, after the giant defender sealed a loan move back to France on Wednesday.
Julien Escude's future at the club could be sorted out this week as sport director Pierre Dreossi is set to meet Ajax officials on Thursday
The Amsterdam club have already had one bid for the player rejected but an improved offer is expected to be put on the table when the relevant parties meet later in the week.
