Arnaud is a middle-aged French man in GTA IV: The Ballad of Gay Tony and meets Luis Lopez as a random character. The two get along and after a conversation and Luis takes him to a massage spa for an appointment. The second encounter, Luis finds Arnaud after a night of Chinese opium laden bondage with some Brazillian prostitutes and was left on a street corner beat up with his wallet stolen by a pimp. Luis drives out with Arnaud to Bronco Avenue.
Massage Spa you take Arnaud to is called "Cum Ming, Massage Spa", which is one of Rockstar`s sex jokes, referring to "special offers" in such places.