Castrogiovanni suspended over PSG Vegas party
Racing also said they would open judicial proceedings against the Argentine-born front rower.
While Racing were in Nottingham beating Leicester Tigers 19-16 to reach their first ever European Champions Cup Final on Sunday, Castrogiovanni was in Las Vegas with PSG players celebrating their 2-1 French League Cup victory over Lille on Saturday.
Wearing sunglasses and displaying a distinctive tattoo on his naked torso, Castrogiovanni appeared in a photo on PSG star forward Zlatan Ibrahimovic's Instagram account alongside the Swede and Argentine playmaker Javier Pastore.
"Following the publication in the press today [Tuesday] of photographs showing Martin Castrogiovanni together with Paris Saint Germain footballers this weekend in Las Vegas, while the whole of the rest of the club's squad were in Nottingham to tackle a European Cup semifinal, Racing 92 have decided to temporarily suspend its player and begin judicial proceedings," said a statement from the Parisian Top 14 outfit.
Castrogiovanni is friends with several of PSG's Argentine contingent, including Pastore and winger Angel Di Maria.
A number of PSG players, including Ibrahimovic, Pastore, Italy midfielder Marco Verratti and his compatriot Salvatore Sirigu went to Vegas with the permission of their club - they have already sewn up the Ligue 1 title and their only significant remaining fixture is the French Cup Final against arch-rivals Marseille on May 21.
A number of attractive young bikini-clad women also appear in the selection of photographs shared on Ibrahimovic's Instagram account.
Castrogiovanni, 34, joined Racing from Toulon at the start of this season on a one-year deal with an option for a further season.
He was not included in the squad picked to play Leicester at the weekend.
Agence France-Presse