Se regarder le nombril

Literally: To stare at one's own navel

Example: “Il passe son temps à se regarder le nombril au lieu d'écouter les autres.” — He spends his time navel-gazing instead of listening to others.

English equivalent: To navel-gaze

Origin: No source dates the phrase itself with any confidence — what is well documented instead is the symbolism it draws on. The navel marks the point of attachment to the mother for nine months before birth, which already makes it a natural emblem of self-origin. Vitruvius, writing on architecture, described the human body as naturally centered on the navel: arms and legs spread to their full extent trace a circle whose middle point falls exactly there. That reading — the navel as literal center of a person — is old enough and widespread enough (it turns up in Buddhist thought too) that a person who can only look at their own navel is, quite precisely, a person who has made themselves the center of everything.