Pet-related fees across French accommodation generally fall into the same categories found elsewhere in Europe: a one-time cleaning fee, a per-night or per-stay charge, or occasionally a refundable deposit. Which one you'll meet depends heavily on the property type — gîtes and self-catering rentals lean toward a flat one-off fee, while hotels more often add a per-night charge instead.
Refundable deposits specifically for pets are relatively uncommon in mainstream French accommodation, appearing more often at higher-end properties or where a listing has had previous pet-related damage. As elsewhere, the fee amount is set by the individual property, not standardised by any booking platform or accommodation network.
Always get the figure confirmed in euros and in writing before arrival — a fee mentioned informally in an email or over the phone, especially at a smaller family-run property, can sometimes differ from what actually appears on the final bill if it wasn't pinned down clearly in advance.