Nouns ending in -tion are feminine.
The suffix forms abstract nouns of action or state.
Is révolution masculine or feminine?
larévolution
The rule behind it
99.8% of -tion nouns are feminine
In context
Après la Révolution, la France devint une République.
After the revolution, France became a republic.
Le germe de la révolution est la répression.
The seed of revolution is repression.
J'écris une étude de la Révolution française.
I am writing a study of the French Revolution.