Todibo, 20, knows he will not continue at Barca following his loan spell at Schalke.
But in an attempt to improve their squad after qualifying for the Champions League, Rennes are pushing hard for Todibo.
Rennes finished third in Ligue 1 so will have to go through two rounds to reach the Champions League group stage.
Entry into the group stage would bank the club €15.25m, so they want to be well prepared.
And Todibo, who played for Toulouse before he joined Barcelona in 2019, is a player they believe can help them.
Todibo has only played five games for Barca but is a highly-rated talent who the club value at €25m.