(Bloomberg) -- Emmanuel Macron is holding firm on Brexit: the Northern Ireland protocol as well as other provisions of the Brexit agreement are non-negotiable.

In a news conference in Paris before a Group of Seven summit, the French president reiterated that the deal signed by the U.K. in December was set in stone. “Nothing is negotiable,” he said. “It isn’t serious to want to review in July what we completed after years of discussions and hard work.”

U.K. Prime Minister Boris Johnson agreed less than two years ago to the terms that created a trade border in the Irish sea. But tensions over the issue have been rising for months, roiling supermarket supply chains and stirring violent protests among Northern Ireland’s unionists.

The EU has warned it could impose trade tariffs unless the U.K. falls in line. Macron is set to discuss the issue and the access of French fishermen to U.K. waters during a meeting with Johnson on Saturday, on the sideline of the G-7 in Cornwall, England.

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