Paris Saint-Germain have commissioned an American company to study the possibility of building a new stadium after the city's authorities and Parc des Princes owners said they were against selling the ground, a source told AFP on Tuesday.
PSG have played there for almost 50 years but Paris Mayor Anne Hidalgo said in January the stadium "is not for sale" and "will not be sold" to the Qatari-owned club.
PSG have made acquisition of the ground in the city's leafy western suburbs a condition for carrying out modernisation and expansion works to the tune of 500 million euros ($536 million).
In November, PSG president Nasser Al-Khelaifi told Spanish sports newspaper Marca that PSG were "no longer welcome" at the Parc des Princes, adding they were looking at "other alternatives".
Renovating a nearby horse racing track is reportedly one option.
Legends Hospitality will carry out research alongside Canadian real estate advisors Colliers.
Inaugurated in 1897 then remodelled in 1972, the former velodrome, with its 48,000 capacity, has been home to the club since 1974.
The current 30-year lease began in 2014.
Legends Hospitality runs Los Angeles' Sofi Stadium, Dallas' AT&T Stadium and has worked with English Premier League clubs Tottenham and Liverpool.