Stade Francais back-rower Hendre Stassen faces a possible four-year suspension after his "B" sample tested positive for an elevated level of testosterone, his lawyer told AFP on Tuesday.

The South-African-born Stassen, 21, will appear at a hearing of France's anti-doping body later in the day.

He was provisionally banned by his club on July 12 after failing a random test following a Top 14 match in mid-May.

The Parisian outfit's president Hubert Patricot told AFP they would wait until the end of the investigation before making a disciplinary decision.

The suspension marks further trouble for Stassen who is currently the subject of a police investigation in South Africa after he allegedly assaulted 26-year-old dentist Markus Botes outside a Pretoria nightclub during the early hours of June 15.

Botes required corrective surgery prompting the charge to be elevated to the more serious crime of assault with the intent to commit grievous bodily harm.

Stassen featured 18 times for Stade Francais last season having arrived in the French capital in October from the Blue Bulls.