On this knowledge base, the marketplace with a native French interface is WeTheNorth (WTN). The interface is fully bilingual English/French, including vendor messages and dispute pages — not a thin translation layer.
Canadian focus
WTN’s audience focus is Canadian. Shipping defaults to Canada-only and most vendors ship domestically. The name is a Toronto Raptors slogan. For a French-speaking Canadian buyer the language and shipping defaults make WTN the practical choice.
How the bilingualism is implemented
WTN switches the interface language based on an account preference. Both languages are first-class — the French isn't machine-translated and isn't fallback-to-English. Vendor messages also carry parallel French copy where vendors have written them that way, which is most of them given the Canadian buyer base. Moderation is bilingual: dispute reviews accept evidence in either language.
Why no other markets are bilingual
Most Tor markets are English-only because that's the default vendor and buyer language on the network. WTN's Canadian focus made French support cost-effective — there's an actual French-speaking buyer population to serve. Other markets would have to translate their entire interface to capture a much smaller addressable audience, and the math doesn't currently work.