RC Lens appointed Toppmöller as their new coach in June 2026, signing a contract until mid-2028. However, the German coach has been unable to leave his mark on the team, winning only one of their first four Ligue 1 matches. The team drew 2-2 against Le Mans in their last match, which has ultimately sealed Toppmöller's fate.
Toppmöller's results outside the Ligue 1 have been better, with the team winning the Trophée des Champions and a 3-2 win against Slavia Praag in the Champions League. A conflict between Toppmöller and the club over video analyst Nelson Morgado is reported as the reason for his dismissal. According to Sky, Toppmöller and the club were unable to come to an agreement over Morgado's role in the technical staff, leading to an unworkable situation.
Yannick Cahuzac is mentioned as a potential candidate to take over as the new coach. Cahuzac is a former midfielder who has been working as an assistant coach to Toppmöller since the summer. He is expected to lead the team alongside Bilal Hamdi in their next match against Monaco.