Chelsea star N'Golo Kante has been criticised by Frank Leboeuf, who feels the midfielder is "timid" and lacks leadership skills.
Kante has only started one of France's World Cup qualifiers in this campaign despite his stunning form for Chelsea, which has led to him becoming the hot favourite to be named PFA Player of the Year.
The 25-year-old is closing in on winning back-to-back Premier League titles having helped Leicester City to glory last season.
But while Leboeuf acknowledges Kante is already good enough to be a crucial part of the team for Chelsea or France, he feels the midfielder is lacking in some key areas.
"The lad is vital to Chelsea, but he is not a boss as he is not a good talker," Leboeuf said to RMC.
"He is timid and lacks the necessary scope. He is an incredible soldier, and a warrior, but he has neither the personality nor the calibre of a leader.
"He is shy and lacks stature. Is he a 'boss' at heart? I don't think so. At Chelsea, in the middle of the stars, he is Mr Essential and Conte counts on him, but he never makes him the boss.
"He doesn't have the game of a boss - he is not a Zinedine Zidane figure."
Kante is with the France squad ahead of their World Cup qualifying match away to Luxembourg on Saturday and high-profile home friendly against Spain next Tuesday.
Leboeuf, who played for Chelsea and Les Bleus in his playing days, added: "He is not even a leader when it comes to technique. He is a lad who will win you the ball back 800,000 times every game.
"You can sum him up in one sentence. He is the engine, but not the driver.
"He can be the engine of the France team without being their boss. He doesn't yet possess the calibre required."
Leboeuf thinks Kante's kind nature could ultimately count against him in the battle for a France starting spot.
"He would not be a problem if left on the bench, but maybe if you leave Paul Pogba on the bench there will be problems," said Leboeuf.
"But it is down to Didier Deschamps, the national coach. He can do what he wants and is the only one who decides."