There will now be a 65-day investigation into the €17 billion acquisition, due to anti-competition concerns, a period that could be extended.
Numericable’s acquisition came after a month-long bidding war, where Bouygues also showed interest in acquiring the operator before being outbid.
The review comes following intense speculation surrounding the French telecoms market, with regulators urging the sector to reduce the number of operating players from four to three.
“The authority considers that the transaction raises serious doubts about hindering competition and requires the opening of a period of detailed examination,” said the authority.