When it comes to Europe's lengthy investigations into Google, Margrethe Vestager, the region's competition chief, is hoping that the third time's a charm.

Ms. Vestager announced on Thursday a new round of antitrust charges against the company — the third set since early 2015 — claiming that some of the company's advertising products had restricted consumer choice. The efforts are part of her continuing push to rein in Google's activities in the European Union, where the Silicon Valley company has captured roughly 90 percent of the region's online search market.

"Google's conduct, based on our evidence, is harmful to consumers," she told reporters in Brussels on Thursday.