Detroit Techno isn't obscure at all. It's a very well-established genre including probably most famously the work by Juan Atkins, Derrick May, and Kevin Saunderson. There have been at least 2 waves of it and it continues to influence electronic music from the fringes to the mainstream. If you're curious about it, I'd recommend Drexciya's The Quest as a starting point.

French House most likely refers the heavily filtered and compressed disco beats of e.g. Daft Punk, which had its heyday in the mid-to-late 1990s.