Toulon have been force to begin alterations on Stade Felix-Mayol in order to bring it in line with the requirements for the Heineken Cup quarter-finals.
Toulon are set to host Leicester on April 7, but need to increase the capacity of their home ground to conform with ERC regulations that require quarter-final venues to have a minimum capacity of 15 000.
Stade Mayol can hold 14 700 spectators and Toulon applied for exemption to the regulation, but in a press release on Wednesday, the French club confirmed that their request had been denied.
The mayor of Toulon has however presented a plan to increase the stadium's capacity to 15 020.
The ERC will inspect the stadium on February 4 before the Toulon city council's safety and security officials do the same on February 7.
If the ERC do not give the changes a green light, Toulon will look to host the games at the Stade des CostiÃ¨res in Nimes or the Parc des Sports d'Avignon.
Toulon have lost just one game on home soil (to Racing Metro in the Top 14) in all competitions this season,