 In addition to his committee assignments, Pfeiffer is a member of the German-French Parliamentary Friendship Group as well as of the Parliamentary Friendship Group for Relations with the ASEAN States.Since November 2015, he has been member of an informal German-Russian working group on energy cooperation, convening parliamentarians of both the German Bundestag and the Russian State Duma as well as business representatives from both countries.Since 2019, he has been a member of the German delegation to the Franco-German Parliamentary Assembly.