Gebhardt is best known for her role in shaping the controversial Services Directive in 2005 and 2006. The directive had aimed at opening up the European Single Market to competition amongst service providers but was, after much political pressure from mostly western and southern EU countries, subsequently watered down by the European Parliament. Gebhardt was parliamentary rapporteur for the directive and played an important role in facilitating an agreement with the European People's Party which allowed Parliament to pass the directive with a huge majority and thereby forcing EU governments to follow their line.