Toulouse Olympique XIII will play in League One next season, ending a four-year absence from Rugby Football League competition.
The French club, who won their domestic title in 2015, will be part of a 15-team league and will also enter the Challenge Cup at the third-round stage.
They join compatriots Catalans Dragons as the only continental clubs operating in British rugby league.
"It will mean big changes for us," said chairman Bernard Sarrazain.
"There are huge financial and sporting challenges, however we thoroughly believe that, after winning the French Elite Championship two years in a row, it is a vital step for the development of our club."
Toulouse previously played in the Championship, a division above League One, before opting to revert to the French game in 2011.
RFL chief executive Nigel Wood said: "We are delighted to welcome Toulouse Olympique back into the competition.
"The board, under the guidance of chairman Bernard Sarrazain and chief executive Cedric Garcia, have worked hard to put together a compelling business case that is predicated on working in partnership with the French Federation.
"Their plan is to ensure there is tangible, coordinated and strategic growth from the impetus of Toulouse's entry into League One that will positively impact on the domestic and national footprint in France."