New York — What you get through Google's powerful and popular search engines may depend on where you live.

A report Thursday from Harvard Law School found at least 100 sites missing from search results when accessing Google sites meant for French and German users.

Most of the missing sites are ones that deny the Holocaust or promote white supremacy. France and Germany have strict laws banning hate speech, while the United States favours freedom of expression even for unpopular viewpoints.

The sites themselves were not blocked. But the effect is the same when users cannot find them, said Danny Sullivan, editor of SearchEngineWatch.com.

"Search engines are an incredible tool for people to locate information on the Web," Mr. Sullivan said. "If you pull a Web site out of a search engine, you are in some degree censoring, in some degree making it inaccessible to some people."

In a statement, Google spokesman Nathan Tyler said the company must occasionally remove sites to avoid legal liability. Such removals, he said, are in response to specific requests and are not done preemptively.

"We carefully consider any credible complaint on a case-by-case basis and take necessary action," Mr. Tyler said. "We only react to requests that come to us."

Google, Yahoo!, Amazon and several other companies run separate sites for different countries, often in native languages and featuring local currencies. The primary, ".com" version is generally considered the U.S. site, though it is accessible from elsewhere, including France and Germany.

Jonathan Zittrain, a professor at Harvard Law School's Berkman Center for Internet & Society, and Ben Edelman, a Berkman researcher, found about 65 sites excluded from Google.de, the German site. They found 113 sites, including the 65, missing at Google.fr, the French site.

Testing was conducted Oct. 4-21.

Mr. Edelman said users would have no inkling of any exclusions unless they compared search results side by side. He suggested Google could better serve users by inserting a "placeholder" where sites are removed due to government or other censorship.

Google's stated policy calls for removing links when site owners request them.

It also removes them for legal reasons, most prominently when the Church of Scientology International complained of copyright violations at a Norwegian site run by critics.

After free-speech advocates complained, Google agreed to notify the site ChillingEffects.org when it gets a copyright-related removal request.

Google, as a private company, is generally not bound by the free-speech guarantees in the First Amendment, which applies to restrictions imposed by government.

But Mr. Edelman said that private or not, the company has a public responsibility as a widely used resource.