FIA President Jean Todt says the decision regarding F1's 2017 tyre supplier ultimately belongs with Bernie Ecclestone.
Earlier this year, the FIA opened the tender process for F1's tyre supplier for a three-year period starting in 2017.
Current supplier Pirelli have applied as too have Michelin, the latter though is demand a move to wider wheels.
But whatever path Formula 1 takes, Todt says it is F1 supremo Ecclestone who will make the final decision.
"We have a division of responsibilities," the Frenchman told Motorsport.com
"The FIA needs to secure the confirmation on the technical and the sporting side, and then it goes to commercial rights holders to address the commercial side.
"Both tyre companies are really adventurous so I am sure they can both supply the sporting and technical side. So what can be the benefit for the promoter and for the teams on the commercial side?"
Pressed as to whether he was in favour of Michelin's proposal for 18-inch wheels, Todt took a neutral approach.
"It's important to explore possibilities," he said. "For that, I will very much rely on people who are more familiar about 13, 18, 19, or 20-inch [wheels]."