• by Wendy Davis  @wendyndavis, September 23, 2009

Siding with Google in its legal battle with Louis Vuitton, an advisor to Europe's highest court said Tuesday that the search company doesn't infringe on other companies' trademarks by allowing the terms to trigger pay-per-click ads.

"Trademark proprietors do not have an absolute right of control over the use of their trademarks," wrote Advocate General Luís Miguel Poiares Pessoa Maduro in an advisory opinion to the European Court of Justice in Luxembourg.

The advocate general wrote that keywords -- even when they're trademarked -- are in themselves "content-neutral." "They enable Internet users to reach sites associated with such words," the opinion states. "Many of these sites will be perfectly legitimate and lawful even if they are not the sites of the trademark proprietor."

While the opinion cleared the use of trademarks to trigger an ad, it also said that using trademarks in the ad copy itself might be confusing.

The advisory opinion issued on Tuesday addresses three separate lawsuits brought against Google in France --one by luxury retailer Louis Vuitton, one by a travel agency and one by a bridal service. The French courts ruled against Google, spurring the company to appeal to the European Court of Justice.

The European court isn't obligated to follow the advocate general's opinion, but does so around 80% of the time, according to the legal blog Out-Law.com.

Google also faces around half a dozen lawsuits in the U.S. complaining about trademark infringement on AdWords. To date, however, Google has won the only case that went to trial -- a lawsuit by insurance company Geico. That trial resulted in a win for Google on the crucial issue when federal district court judge Leonie Brinkema in Virginia ruled that Google didn't violate Geico's trademark by it to trigger pay-per-click ads. Brinkema held there was no proof that consumers were confused by such ads and she dismissed the bulk of Geico's complaint.