In Europe, the agreement would be legally binding for five years, and a third party would ensure compliance, the people briefed on the proposal said. Google could face a fine of as much as 10 percent of its global annual sales for failing to keep its promises.

If it abides by the agreement, though, Google will avoid fines and a formal finding of wrongdoing. Google will also escape the lengthy and expensive antitrust battles that Microsoft faced in Europe over its media player and server software.

Herbert Hovenkamp, a professor of antitrust law at the University of Iowa, said the penalty faced by Google was light. “The ‘no fine’ conclusion is a pretty important one,” said Mr. Hovenkamp, who has in the past been a paid adviser to Google. “The question you have to ask is: Is labeling going to change any consumer behavior? And if the answer is no, then it’s not going to do any good for Microsoft Bing or for any rival search engines.”

Last month, 11 complainants to the European Commission, including Expedia and TripAdvisor, sent a letter to the commission expressing concern that it was not prepared to penalize Google enough. “Google’s search manipulation practices lay waste to entire classes of competitors in every sector where Google chooses to deploy them,” the letter said.

About 86 percent of all online searches in Europe are conducted using Google, according to the Web analyst comScore. In the United States, it has about two-thirds of the market.

Under the terms of the settlement, the details of which were first reported by the Financial Times, search results would look slightly different in Europe than elsewhere.

In areas where Google does not make money from search results, like weather or news, the company will label the results as Google-owned properties. In areas where Google sells ads, like local business reviews, it will show links to at least three competitors. In areas in which all search results are paid ads, like shopping, Google will auction links to rivals.