Nouns ending in -tion are feminine.
The suffix forms abstract nouns of action or state.
Is position masculine or feminine?
laposition
The rule behind it
99.8% of -tion nouns are feminine
In context
Il s'assit en position de méditation Zen.
He sat in Zen meditation.
Il avait une position ferme sur le sujet.
He had a strong stance on the subject.
Tu n'es pas en position de négocier.
You're in no position to bargain.