The PRL grew out of the Francophone part of the unitary liberal Party for Freedom and Progress (PVV-PLP) in 1971 and merged into the Reformist Movement (RM) in 2002.
In Brussels, the French-speaking Liberals co-operated intensively with the Democratic Front of the Francophones (FDF).
In 1993, the PRL formed an alliance with the Democratic Front of the Francophones (FDF), a party standing up for the rights of French-speakers in and around Brussels.
In 1998, the Citizens' Movement for Change, a split-off from the Christian Social Party, joined the alliance, making it the PRL-FDF-MCC Federation.
On a congress in 2002, the German-speaking liberals of the Party for Freedom and Progress also joined and the alliance took the name of Reformist Movement (MR).