On 12 March 2009, it was announced that Contepomi would be leaving Leinster at the end of the season, and that he had signed a 4-year deal to join French side RC Toulon from the 2009–10 Top 14 season.
Contepomi played a role in the Leinster win over Munster in the Heineken Cup semi-final on 2 May 2009. After scoring a drop goal after 15 minutes in, he was helped off the pitch after suffering a knee injury half an hour in. An MRI scan confirmed he tore his anterior cruciate ligament and was expected to be out of action for 6 months post-op. Almost exactly on schedule, he made his Toulon debut on 21 November against Brive, coming off the bench and scoring a penalty in Toulon's 19–10 win.
A knee injury suffered in Leinster's Heineken Cup semi-final victory over Munster in 2009 ruled him out of action for over a year but he returned to Pumas colours in 2010 and won a 31-point haul in their 41–13 victory over Six Nations champions France.