French telecommunications operator Orange has been fined 350 million euros ($380 million) for breaching competition rules in the corporate market, the French competition regulator said on Thursday.

The fine, the biggest the regulator has ever slapped on an individual company, comes after competitors Bouygues Telecom and SFR complained that Orange had been hindering free competition in the business market for fixed and mobile phones since the early 2000s, the authority said.

Bouygues has since dropped out of proceedings after reportedly receiving a large payoff from Orange.

Orange had established a number of anti-competition practices, especially loyalty schemes, that stopped corporates from picking a different operator for even part of their telecoms needs, the authority said.

Orange had also restricted other operators' access to client information it held thanks to its former monopoly position as historic fixed-line operator France Telecom, it said.

The competition authority said it had ordered Orange, which had been cooperating in the investigation, to immediately re-establish a "healthy competition situation" in its markets.