The midfielder who was on loan with Nancy last campaign will team up with the Stade Michel d'Ornano outfit for the new French Ligue 1 season without a purchase option.
Bennasser, 21, who still has a running contract with Monaco until 2021 joins the Caen as a reinforcement in their defence and midfield.
“Considered a priority by Patrice Garande, the Stade Malherbe holds its reinforcement in defensive medium. Under contract with AS Monaco until 2021, Youssef Aït Bennasser (21) was loaned to the Norman club for one year without a purchase option,” the statement reads on the club’s website.
“The Moroccan international, who is expected to perform his first training session with his new teammates on Wednesday afternoon, is likely to experience his first baptism in the "Blue and Red" jersey on Sunday in Lille.”