Iliad said late Thursday it would offer $33 a share for a 56.6% stake in T-Mobile, and $40.5% for its remaining shares, all in cash. In doing so, Niel stole a march on Sprint’s majority owner Softbank Corp, which has failed to present a formal offer for the company despite months of leaks and rumors suggesting it intended to.

Niel appears to be counting on the same logic that was behind his unsuccessful bids for French mobile networks SFR and Bouygues Telecom earlier this year. His relatively small company–only one-fifth the size of T-Mobile–could execute a deal without any of the regulatory concerns caused by the merger of two bigger ones.

However, the first indications are that he may have to raise his game. Bloomberg quoted people close to T-Mobile’s parent Deutsche Telekom AG as saying that the offer was ‘non-competitive’.

Analysts say antitrust concerns could seriously complicate a tie-up between Sprint and T-Mobile, which are the third and fourth-largest networks in the U.S. behind AT&T (T) and Verizon Communications (VZ).

Niel may be an unknown in the U.S. but is one of the most colorful and dynamic personalities in the French business sector. Having made his breakthrough as an entrepreneur selling sex-chat services on Minitel–France’s ill-fated 1980s proto-internet project–he now has an estimated net worth of $9.2 billion, according to Bloomberg’s Billionaires Index, having successfully carved out a large part of the French mobile and internet markets in the teeth of opposition from a powerful state-owned incumbent and companies such as Bouygues and Vivendi SA.

However, the offer for T-Mobile is ambitious even by Niel’s own standards. Iliad’s shares fell 7% early Friday in response to news of the bid, as investors took fright at the scale of borrowing needed to finance the deal. Reuters reported that the company had agreed loan commitments of $13 billion from BNP Paribas SA (BNPQY) and HSBC plc (HBC).