Since losing his Toro Rosso seat, the now 28-year-old Swiss became a top sports car and Formula E driver, and in July helped Pirelli test F1 tyres at Paul Ricard.
But Prost told the Swiss newspaper Blick: "It is a scandal that Buemi is no longer in F1.
"He is still one of the fastest drivers in the world."
Book discounted tickets and reservate your hotel room in our F1 Tickets Shop.
The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.