Reacting to Mbappe and Real Madrid's Champions League elimination by Arsenal last night, Riolo says the summer arrival from PSG is wasting his talent being played out of position.
Riolo is adamant Mbappe won't fulfil his potential until he is played in his best position.
He told After Foot on RMC: "His place is not as number 9. If Vinicius leaves at the end of the season, ok. But for two years, Mbappé has been wasting himself in a role that is not his.
"He does what he can, he scores goals, another thirty this year, some are magnificent, others very easy."
While he acknowledges the former PSG captain's goalscoring efficiency, Riolo believes that it masks a real waste: "From the moment you're up front, it's normal to score. But how long will he waste himself in this position?
"Either he finds a real physique - and he's not far from having it completely - to play again in the position that made him famous, or he persists in wanting to play 9 and he'll waste himself."
The columnist concluded his tirade with a final observation: "We had a fantastic player from the age of 17 to 25, which is already not bad. But now, unless he changes, we won't see the Mbappé we knew again. "