Starting on the left of a 4-3-3 formation coached by Zinedine Zidane, Kylian Mbappe had to wait until the 54th minute to make his mark.
After Ugurcan Cakir failed to clear the ball, France took the lead through their captain, who converted a perfect pass from Michael Olise.
Mbappe did not celebrate, instead clutching his left knee. He tried to continue, but was substituted in the 58th minute, with Desire Doue coming on. He went straight back to the dressing room.
After the match, Zidane said Mbappe had hyperextended his left knee. He could well be ruled out, at the very least, for France's next three matches.
"I think he'll have to return (to Madrid)," Zidane told TF1.
"We won't take any risks. He hyperextended his knee when taking the shot. That's not exactly encouraging if he is to continue."
As a reminder, the Clasico will be played on October 25th. The countdown is already underway in Spain.