French telecoms giant Numericable-SFR has made a €10bn ($11.4bn; £7.2bn) offer for rival Bouygues Telecom.
Shares in Bouygues jumped almost 15% in early trading in Paris after the bid was announced.
A deal between the two would create France’s largest mobile phone operator.
However, the government has already expressed concerns, with Economy Minister Emmanuel Macron saying further consolidation in the sector was “currently undesirable”.
“Now is not the time for opportunistic tie-ups which may be of interest to some people but which are not in the public interest,” he added.
“Jobs, investment and better customer service are the priorities.”
Last year, Numericable parent Altice, owned by billionaire Patrick Drahi, outbid Bouygues to acquire rival SFR.
The board of Bouygues will meet on Tuesday to discuss the offer, reports suggested.