Italians probe the practices of TripAdvisor, Expedia and Booking.com

Italy's antitrust and competition authority is investigating TripAdvisor to see if the user-generated hotel review website does enough to delete fake opinions.

In a statement, it noted concern about some people reviewing places they haven't been, and thus damaging the reputations and prospects of those places.

Italian authorities have also opened an investigation into online travel companies Expedia and Booking.com, saying their agreements with hotels may prevent consumers from getting a better deal.

As Reuters was first to report, the authority's statement says the issue is hotel rate-parity clauses it worries may limit competition.

This latter allegation is well-trod territory for Expedia and Priceline Inc in Europe and not something any competition authority has proven so far.

In January, the United Kingdom's Office of Fair Trading closed down its own investigation into rate parity and competition.

The Italian authorities have been on a tear lately. They also recently said that they're investigating Google, Apple and Amazon over unfair commercial practices.