Emmanuel Macron holds the key to the U.K. getting a trade deal with the European Union. So far he’s keeping it in his pocket.

The French president is standing firm on his demand to keep the same access to British waters his country’s fishing industry enjoys today, according to officials familiar with the talks. That’s angering the British and creating tensions even among his allies within the EU.

As the Brexit talks enter their final critical few weeks, officials on both sides are voicing doubts over whether they can get a deal over the line. EU negotiators say that while they wait for Prime Minister Boris Johnson to offer concessions on state aid — the other major obstacle to an accord — Paris’s stance on fish is becoming a second major focus of concern.