Signs of trouble have been dogging the Trans-Atlantic Trade and Investment Partnership, a U.S.-EU free trade zone encompassing half the world economy, for months but only today have we seen the accumulated tension bubble up to the surface.

French president Francois Hollande said Tuesday that France "will never accept" challenges to its farming and culture in exchange for better access to U.S. markets. "That's why at this stage, France says no," the Socialist leader said at a conference on left-wing politics.

Earlier Tuesday, French Trade Minister Matthias Fekl told Europe-1 radio that negotiations "are totally blocked" and that a halt to talks "is the most probable option." He insisted on better farming and environmental protections, adding that "in its current state, France cannot sign it."

"Europe is giving a lot ... but receiving very little in return," he said.