PARIS—Dominique Anract, a baker in Paris's 16th arrondissement, sells about 1,500 baguettes every day, and most of them he wouldn't want to eat himself.

The vast majority of his customers, he says, choose the whitest, least-baked baguette on display. So he and his team take 90% of the loaves out of the oven before they are done.

"If those were for me, we'd keep them all in two to three minutes longer," he says. "But that's not my call—it's the customer's."

One of the great symbols of French gastronomy is under siege. Renowned for its distinctive shape and crusty exterior, the baguette risks becoming known for something else, too: being undercooked and doughy.