But Dodi's father Mohamed al Fayed - who believed the couple were murdered - insists the Frenchman was not drunk and the samples had been switched.
And now Sebastien Trotte, a former barman at the Paris hotel, has told the hearing Mr Paul drank two 4cl measures of Ricard - aniseed spirit.
He had been waiting with bodyguards in the Bar Vendome pending the couple's departure in August 1997. an Burnett QC asked Mr Trotte: "Did he appear to you to have had too much to drink?"
Giving evidence through an interpreter by video link from Paris, he replied: "No."
Mr Burnett asked if he appeared "in any sense drunk?" to which Mr Trotte said "no".
The former barman said Mr Paul - who also died in the crash - and the bodyguards "were all a bit nervous".
He added: "Mr Paul had been called back from his home and they were waiting for the signal for Princess Diana and Mr Fayed to leave." (Sky News)