“We are clearly in favor of a mix and having the choice of any software, open or mixed, whatever suits governments,” Mr. Vassallo said. “It’s not putting a particular preference in front of the buyers that will solve the issue of working across borders. It is the opposite, having more choice — then more technical solutions and innovation will be available.”

Google, I.B.M. and Oracle, which in January bought the open-source software pioneer Sun Microsystems, are the main supporters of Open Forum Europe, a group based in Brussels that has been lobbying for an explicit endorsement of open-source software. Graham Taylor, the Open Forum Europe chief executive, says more than 90 percent of European governments end up buying proprietary software products because of inertia, lack of knowledge about open-source alternatives or the fear of switching to a new supplier.

Lobbying by Microsoft and other European companies that make proprietary software, like Ericsson and Alcatel-Lucent, has also been formidable, Mr. Taylor said. Ericsson and Alcatel-Lucent sell proprietary software to governments to, among other things, help run their internal agency telecommunication systems. About 50 companies, groups and individuals submitted comments to the commission on both sides of the issue.

“We are up against a very big, powerful lobby,” Mr. Taylor said. “The makers of proprietary software are protecting the standards that are already in existence. They are also, of course, trying to preserve their market positions.”

In Europe, the birthplace of the Linux open-source operating system and MySQL open-source database software, which is now owned by Oracle, open-source activists have been increasingly challenging local government administrators when they decide to renew software licenses for the products of Microsoft and other proprietary vendors.

In Bolzano, a city in northern Italy, a Linux users group in May challenged the provincial government’s decision to spend €2.2 million, or $2.8 million, over three years to renew and upgrade software licenses for 161 Microsoft servers and 4,000 desktop computers used to run the day-to-day business of local government.

“We are afraid the administration is getting trapped in this weird logic of software license updates and vendor lock-in,” said Daniele Gobbetti, 31, the president of the Linux Users Group in Bolzano.