Ha ha, classic. But you know, even if the owner had been a Breton and his staff Breton too, I very much doubt that any of them would speak Breton in that Parisian crêperie (as, for starters, they would anyway most probably had been brought up in Paris/Greater Paris, Between 1 million and Bretons or people of Breton origin in Greater Paris, massive diaspora). It's due to very strong internal migration movements within France (impoverished countryside => urban areas) in the second part of the 19th century (advent of railway, rural exodus, industrialisation) and 1st part of 20th century from poor provincial areas, cue a Breton diaspora towards cities, particularly Paris. In the Greater Paris area, more than one million people claim Breton heritage. Ditto people from the Auvergne regions – particularly Puy-de-Dôme, Cantal and Aveyron départements – and the 2 Savoy départements, between them they own half of the 20,000 bars, cafés and restaurants in Paris proper and a good number in Greater Paris. Even in Brittany, few people speak Breton fluently. They have the fully bilingual Diwan schools in Brittany (and many high schools are partly bilingual) and Breton is reasonably reasonably well spoken in some pockets of Central, Western Brittany and North-West Brittany in the Roscoff-Morlaix area (what’s called in French “La Bretagne bretonnante”) but by and large out of the 5 million Bretons, I’d be very surprised if more than 150,000-200,000 of them spoke Breton or Gallo (Eastern Brittany) with any fluency (although a decent % would have some knowledge of it, “some” meaning in most cases just the odd words or phrase, in other words the very basics).