Esteban Ocon has no exit clause in his new three-year contract with Alpine that would allow him to switch to Mercedes, the Formula One team's boss Laurent Rossi said on Friday.
The 24-year-old Frenchman is managed by Mercedes and served as that team's reserve driver before joining Renault-owned Alpine.
Mercedes could be looking to replace Valtteri Bottas at the end of the season, while seven times world champion Lewis Hamilton is also out of contract then although he is expected to stay.
"He is a Mercedes-managed driver, that's about it," Rossi told reporters at the French Grand Prix at Le Castellet. "He stays with us for the next three years."
Rossi said Ocon reminded him of four times world champion Alain Prost.
"He is very good at extracting the maximum out of the car, and it shows, constantly improving," he said. "He is a good team mate. He is good with the rest of the team...He is basically pushing everyone up."