Google said it would file on Friday with the European Commission for permission to acquire rival DoubleClick for $3.1 billion.

We are asking the European Commission to look at the proposed acquisition. We believe this deal is positive for both users and advertisers and fosters competition, Julia Holtz, Google's competition counsel, told Reuters.

DoubleClick is in the business of on-line advertising, as is Google. Google has already filed with the U.S. Federal Trade Commission and with the Australian competition regulator.

DoubleClick connects ad agencies, marketers and Web site publishers, and has more than 1,500 corporate clients.

Rivals including Microsoft and AT&T Inc have asked U.S. antitrust officials to look closely at the proposed takeover, saying Google could gain too much control over online advertising.