Abritel FR started as a classifieds site for holiday rentals back in the mid-1990s, and it still operates with that vibe. Less polished than Airbnb, but somehow more French. The platform specializes in longer-term holiday rentals rather than city breaks: villas in Gironde, ski apartments in the Alps, beachfront places in Guadeloupe and Mauritius. They've got good coverage of less obvious destinations too, like Alata in Corsica and the Costa Brava just over the Spanish border.
The listings skew toward families and groups rather than solo travelers. Many properties are owner-managed, which means you sometimes get a slightly rougher around the edges experience, but also more character and often better value than the big standardized platforms. Prices can be shockingly cheap if you hunt around, especially for island destinations: Mauritius from 38 euros, Guadeloupe from 50 euros. Those aren't per-night rates for luxury, but they're still worth investigating.
If you're renting a villa in France or planning a longer beach break, it's worth comparing Abritel against the usual suspects. The site's in French, which isn't ideal for UK visitors, but nothing insurmountable. The cancellation policies vary wildly by property, so read the small print properly before you book.