Upvote:0
A new uniform format (or common format) had been adopted by the EU in 2017 and issued since 2019. Its use has been mandatory for member states (incl. EEA and Switzerland) since 2021. Existing cards will remain valid until their expiry dates or by 3 August 2026 (whichever is the earliest).
Upvote:3
The common format residence permit is indeed a red and blue (or pink and purple, depending on the ambient lighting) card with a bull and stars. Older ones will not have a chip, but they remain valid even without a chip. France added the chip to theirs in June 2011.
France residence permits after and before June 2011:
Image source: Government of France
You will need to show both your passport and this residence permit when you check in for your flight in Africa, so that the airline can confirm your ability to transit the UK. They will deny boarding without it.