The U.K.'s decision to leave the European Union created uncertainty in several sectors of the economy, including the autos industry.
For instance, Nissan, owned by French car-maker Renault, has a factory in Sunderland which employs thousands of U.K. workers.
Speaking to CNBC at the Paris Motor Show, Carlos Ghosn, chief executive and chairman of Renault, was asked about the future of the company's operations in the U.K. following Brexit.
"I'm not confident of anything until I know what's going to be the rules," he told CNBC's Nancy Hungeford. "That's what we have said to the British government."
Ghosn said a crucial factor is whether or not the U.K. stays in the European single market.
"Eighty-five percent of [vehicles produced in Sunderland] goes to Europe, so for us, the trade relationship between Europe and the U.K. is extremely important," he said.
"Unless we know what are the rules, it's going to be very difficult to make any statement."
Renault was present at the Paris Motor Show to display its new concept car, the Renault TREZOR, which is intended to represent a new design direction for the company.