Yelp is suing Web sites that take cash from restaurants in exchange for inundating it with phony positive reviews.

Yelp’s lawsuit said sites such as Yelpdirector, Revleap and Revpley are trying “to undermine the integrity of Yelp’s platform” by flooding it with spam and false accolades.

“These offers are scams,” the company said. “Today we’re taking a stand to protect business owners from falling prey to these misleading companies.”