Complex sentence: The party replaced, in 2002, the Citizens' Movement founded by Jean-Pierre Chevènement, who one left the Socialist Party in 1993 due to his opposition to the Gulf War and to the Maastricht Treaty.
Split into simpler sentences: The party replaced, in 2002, the Citizens' Movement founded by Jean-Pierre Chevènement. This one left the Socialist Party in 1993, in due to his opposition to the Gulf War and to the Maastricht Treaty.