Bob Denard lead a group of 20 French mercenaries in Angola. They were supported by the French SDECE and the CIA from Kinshasa. They called themselves the "Hoods", after "Robin Hood". The first few "French hoods" arrived in Kinshasha on the 10th January 1976 where they were trained for two days before being sent onwards to Solva Porto. The rest arrived in Kinshasha on 27th January 1976.
They went on to assist the UNITA group of Jonas Savimbi and saw action against the MPLA. One of the volunteers was KIA the son of a French Army general.
There is also evidence that some French mercenaries were in Angola as early as 1975.
It's also worth mentioning that 13 or so Portuguese mercenaries were recruited by Col Sanntos e Castro, but they never arrived in Angola.