Kylian Mbappe, Antoine Griezmann and Ousmane Dembele were on the scoresheet for the World Cup winners against the Euro 2016 semi-finalists, who had Neco Williams sent off for handling the ball in his area.
Deschamps handed goalkeeper Hugo Lloris his 100th start as captain but midfielder N'Golo Kante was rested after winning the Champions League with Chelsea on Saturday.
Deschamps' counterpart Robert Page, standing in for regular boss Ryan Giggs as the former Manchester United winger faces charges of assault, kept Juventus midfielder Aaron Ramsey on the bench having last played in Serie A in April.
Benzema, who had scored twice against Armenia at the Allianz Riviera on his last international appearance, forced a save from Danny Ward after four minutes.
His 82nd cap took a turn for the worse after 22 minutes despite his shot that resulted in Neco Williams' red card and a penalty.
The Real Madrid forward stepped up but Ward saved the spot-kick superbly low to his right.
Les Bleus stepped up the pressure with an extra man and broke the deadlock 10 minutes before the break.
Adrien Rabiot's shot from outside the box was pushed away by Ward but Mbappe poked home the volley for the opener.
Griezmann doubled the lead three minutes into the second half with a curled effort past a fully-stretched Ward.
Dembele claimed his side's third goal -- and just his fourth for his country -- with 11 minutes left after Benzema's shot fired back off the post.
France face Bulgaria on Tuesday before opening their Euro 2020 campaign by playing Germany in Munich on June 15.
Wales host Albania on Saturday before heading to Baku to play Switzerland on June 12.
