The European Commission on Tuesday opened a "deep investigation" into French state support for plans by EDF, a state-owned utility, to build six new nuclear reactors.
"We will of course do everything possible to conduct the investigation and our assessment as quickly as possible," the Commission said, noting the process is complex and requires close cooperation with French authorities.
Paris submitted a request last year seeking EU approval for measures to support EDF in its project to construct six new reactors.
Under the plan, EDF would receive a subsidized public loan covering up to 60% of construction costs, alongside a "contracts for difference" mechanism on the electricity produced to ensure repayment.
The scheme is central to France's plan to renew its aging nuclear fleet and add about 10 gigawatts of capacity, with the first reactor scheduled to enter service in 2038.