France has rejected a US proposal that would allow companies to abandon the proposed international tax reform, said Finance Minister Bruno Le Maire said on Friday, urging Washington to negotiate in good faith.

US Treasury Secretary Steven Mnuchin raised serious questions about the OECD proposals for international tax reform in a letter released Wednesday, urging international officials to put forward the idea of a “safe harbor regime,”  Reuters reported.

Le Maire noted that this would mean that American companies may, at their discretion, participate or refuse it, which, according to him, will be unacceptable to France and other OECD countries.

He called on Washington to talk on the basis of the binding new tax rules and said that if efforts in the OECD are directed to EU countries, negotiations on a European digital tax should be resumed.