From the Freiburg official site regarding Santamaria to Rennes:
“Baptiste expressed his wish to return home to France with his family to us at quite short notice. We made some difficult and careful considerations and decided to make the transfer possible due to his personal situation and the deal’s financial conditions”, said chairman Jochen Saier. “It was clear for us that we could only agree to this move if we could fill the position with the same level of talent as Baptiste. We are currently in the final discussions to do this.”