The Slovenian club previously already confirmed Mitrovic's departure, but now the French team confirmed the signing of the Serbian international.
The 31-year old spent majority of the season on the sidelines, recovering from a tough knee injury. Therefore, Mitrovic never really found his rhythm in Celje PL, but has proved himself numerous times in the past. Mitrovic only recorded 6 SEHA – Gazprom League appearances for Celje PL, but has scored 14 goals and 11 assists. He joined the Slovenian champions from their rivals Gorenje Velenje, where the 31-year old had 56 goals and 40 assists during the 16/17 season. Serbian centre-back started his career in Metaloplastika, and played one SEHA season with the club, scoring 70 goals in 13 matches in the first season.
Mitrovic also has experience playing in Denmark and Norway before his move to Slovenia. Cesson-Rennes are the former club of Celje PL's pivotman Igor Anic.