The French Rugby Federation (FFR) announced on Saturday that its board had approved a private equity firm's investment in the Six Nations.
CVC Capital Partners will take a 14.3% stake in the annual tournament at a cost of 350 million euros ($435 million) over five years.
An additional 67 million euros could be paid to the six national governing bodies if certain objectives are met at the end of three seasons leading up to 2028.
"If this project comes to a succesful conclusion, CVC will become the seventh partner of the Six Nations, to help the unions to develop their long-term economic potential," FFR president and World Rugby vice-chairman Bernard Laporte said in a statement.
"At the same time the unions conserve their exclusive power over laws, the sporting aspects and the competition's organisation," he added.
Last week, the women's and U20's events were been postponed due to coronavirus travel fears.
Organisers said they were hopeful the men's competition will go ahead with France heading to Italy in the opening game on February 6.
In July, Laporte told AFP the fund had decreased its original offer due to the Covid-19 pandemic.
CVC, which formerly owned a controlling stake in Formula One, has already purchased stakes in the parent company Manchester City in the English Premiership and in the Pro14 domestic leagues.