Zidane insists his former Real Madrid team-mate should not have his ability questioned - nor his motivations for being in the French capital.
He said: "Beckham is going to surprise you.
"He is a truly great professional. He is going to show some professionalism and that cannot hurt some of the guys today.
"He didn't come to play 90 minutes every match. He will bring his touch, and that he is capable of doing in 20 minutes, half an hour.
"He has a way of striking free-kicks, putting his foot against the ball, which is different from others.
"He's a guy who loves to play, at 37-years-old he's still here, he doesn't do it for anything other than passion."