AN INVASION ON A SESAME SEED BUN:

It has the taste of the forbidden, the illicit — the subversive, even,” said Hélène Samuel, a restaurant consultant here. “Eating with your hands, it’s pure regression. Naturally, everyone wants it.”

It is a startling turnaround in a country where a chef once sued McDonald’s for $2.7 million in damages over a poster that suggested he was dreaming of a Big Mac. Hamburgers were everything that French dining is not: informal, messy, fast and foreign.

The delicious taste of the forbidden. But, naturally, one must not transgress too far:

“We’re a little terrified of making a mistake,” said Ms. Samuel. “We cling to things like the soft buns, sweet-and-sour pickles, onions, tomatoes, cheese. We need these guideposts because we don’t have the history, the context. Otherwise, for us, it’s not a burger. It’s a hot sandwich.”

Lighten up. You can even steam ’em. Leave the tradition-bound approach to Louis.