In a press release on its website, EDF writes that the joint project concerns both conventional nuclear power reactors and small-scale modular reactors.
Expressen was the first to report on the agreement.
In October, Finnish Fortum began a preliminary study on the conditions for building new reactors, with a main focus on smaller nuclear power plants.
"We are happy to collaborate with Europe's leading nuclear power company, both within the framework of our feasibility study on new nuclear power in the Nordics," says Petra Lundström at Fortum in the press release.
EDF CEO Vakis Ramany says that together the companies will "create opportunities for successful cooperation in Finland, Sweden and Europe".
The French company writes that it aims to launch a fleet of so-called EPR reactors around Europe.
Such reactors have been developed by, among others, EDF and are so far only in operation in China.
The Finnish nuclear power plant Olkiluoto's repeatedly delayed third reactor is of the EPR type, and is expected to be commissioned in January.
According to one of the points in the so-called Tidö Agreement - the agreement between the governing parties and the Sweden Democrats - Sweden must re-direct energy policy and invest in building new nuclear power.