Former All Black Ali Williams and Australian international James O'Connor were arrested in Paris Saturday in possession of cocaine, police said.
The pair, currently playing for French clubs Racing 92 and Toulon respectively, were stopped at around 3:00 am (0200 GMT) outside a night club near the Champs Elysees and found to be in possession of two grammes (0.07 ounces) of cocaine, police added.
Ex-All Black forward Williams, aged 35, earned 77 New Zealand caps between 2002 and 2012 and currently plays in the second row for Racing 92 in the Top 14 French club championship. He was part of the All Black team that won the 2011 World Cup and helped Toulon to three European Cups.
O'Connor, 26, who plays on the wing or at fullback for Top 14 club Toulon, appeared 44 times for Australia between 2008 and 2013. He made his debut at 18, the second youngest Wallaby in Australian rugby history.
The two men are being held at a police station in the 17th district.
Toulon president Mourad Boudjellal told AFP he had "no comment" to make following the arrest of Williams. Racing 92 officials were not immediately available for comment.
The arrest of Williams is a new blow for Racing 92, crowned champions of France in June.
Three Racing players including former All Black stars Dan Carter and Joe Rokocoko were cleared of doping charges in October by a French Rugby Federation commission. The probe was ordered after the trio tested positive for corticosteroids following last season's domestic Top 14 final. Corticosteroids can be used to combat pain, inflammation or allergies
France's Anti-Doping agency has appealed against the decision and summoned the trio to appear at a hearing, for which no date has yet been fixed.
More unwelcome trouble for the club came earlier this month when Carter, 34, the two-time All Black World Cup winner and three times world player of the year, was stopped for drink-driving in Paris on February 15 and admitted to making a "massive error in judgement."