Yelp contends that Google favors its own services over rivals in search results in both Europe and the United States, even when the Google content is lower quality or less relevant. Google has said it tries to give people quick answers to their questions instead of sending them to another site.

In 2013, the F.T.C. closed an investigation into Google’s search practices after the company agreed to some narrow changes.

“For so many years, U.S. companies were having to seek relief abroad because our own enforcement agencies weren’t critically examining the questionable behavior of large firms like Google,” Yelp’s Mr. Lowe said.

The European Commission also opened an investigation of Amazon last September and has received informal complaints from eBay and the European e-commerce site Zalando, according to a person involved in the discussions who was not authorized to disclose them.

A central argument against the tech giants is that other companies must use their platforms because that’s where their customers are. With that leverage, the argument goes, the tech giants force terms on other companies that are unfair and deepen their dominant positions.

Apple makes developers use its App Store to distribute their apps on iPhones and collects up to 30 percent of revenue made through activity inside the app. Spotify recently argued to European competition authorities that Apple used its App Store to punish Spotify’s app and favor Apple’s competing service.

Apple has said that it welcomes competition and that it has long helped Spotify reach customers. The only time it has requested changes to Spotify’s app is when it “tried to sidestep the same rules that every other app follows,” Apple said in a statement in March. Spotify had directed customers to pay it directly so Apple wouldn’t get a cut.