Potential purchasers of three French motorways face a third round of bidding as the government plays out what is believed to be its first private equity-style auction.

Sources at the bidding companies said the government had indicated it might extend the process after supposedly final proposals were submitted this month. A senior adviser to one of the bidders said the government was trying to get the highest possible price through a bidding war. The assets have been valued at €14.5bn ($17bn).