Apostille or embassy legalisation for France?
France signed the Hague Convention in 1965. That single fact decides your route. You do not need a French consulate to stamp anything, and no embassy step applies. One apostille from the London office is the correct and complete step for France. The older phrase document legalisation for France still turns up on out-of-date forms, but for a Convention member the apostille is the whole of it.
France's Hague status and what it means
Membership means France agrees to take a stamp from the country where the paper was made. The stamp says the seal or signature on your paper is real. It does not say the French side must act on what the paper contains. A French notaire or mairie still reads the text and applies its own rules to it, exactly as it would to a paper made in France.
The London to France route step by step
Start with the paper itself. The London office stamps public records and signed deeds, not copies you made at home. If you only hold a copy, get a fresh certified one from the register or from the body that issued it. Then send it in. An apostille from the United Kingdom to France travels with the paper, so keep the two together from that point on.
Cost and timing for this route
The fee is £45 per paper by post. Registered businesses may take the next-day route at £40 per paper. Those are the office charges and nothing else. Post times sit on top, and a busy spell adds days to them. Plan for the round trip rather than a same-week deadline, and send every paper you need in one go.
What French offices look for
French offices work in French. Where a translation goes with the file, the stamp still belongs to the original paper — it covers the signature underneath, not the translated text. Keep the pages fastened as the office left them, because a stamp parted from its paper proves nothing. Send the translation alongside the stamped original rather than in place of it.