He then served with generals Antoine Chanzy and Charles Denis Bourbaki, participated with the latter's disastrous retreat to Switzerland, and fought against the Paris Commune.

[3][1] In 1882 Déroulède, along with the historian Henri Martin and Félix Faure, founded the Ligue des patriotes, to promote France's "revanche" against Germany.

Déroulède served initially as the deputy to vice-president Faure, and the league quickly attained a membership of 182,000, a relatively large number for the time.

[5] After the rise of General Georges Boulanger, Déroulède attempted to use the Ligue des Patriotes, until then a non-political organization, to assist his cause, but was deserted by many of the league's members and forced to resign his presidency.

After the funeral of President Félix Faure, on 23 February 1899, he endeavoured to persuade General Gaudérique Roget to lead his troops to the presidential palace.

After a long trial before the French Senate serving as the high court, he was sentenced, on 25 January 1900, to ten years' banishment from France, and retired to San Sebastián in Spain.

As a member of the chamber Paul Déroulède was an opponent of colonialism, believing that it distracted from more pressing foreign policy issues in Europe, especially German control of Alsace and Lorraine.

Déroulède was also an Anglophile, believing that an alliance or agreement with Britain was essential for defending France against Germany and enabling the recapture of Alsace-Lorraine.