Answer
Rennes, a French football club based in Rennes, was Ismaila Sarr's previous club before he joined Watford. Sarr, a Senegalese professional footballer known for his speed and dribbling skills, began his career with the Senegalese club Génération Foot before moving to Europe. He joined FC Metz in 2016 and made a significant impact, leading to his transfer to Rennes in 2017.