Remarquer vs. s'apercevoir

In French, both 'remarquer' and 's'apercevoir' translate to the English word 'to notice', yet they are used in slightly different contexts and carry a nuanced difference in meaning. Understanding these differences is key to utilizing them properly in conversation or writing.

Remarquer

'Remarquer' refers to the action of consciously observing or pointing out something that may or may not be obvious, similar to 'remark upon' in English.
J'ai remarqué que tu étais très calme aujourd'hui.
(I noticed you were very quiet today.)
Elle a remarqué une faute dans le rapport.
(She noticed an error in the report.)
Il a remarqué son nouvel accessoire tout de suite.
(He immediately noticed her new accessory.)

S'apercevoir

'S'apercevoir' implies a realisation of something that was not initially obvious, similar to 'become aware of' or 'realise'. It often refers to less tangible things than 'remarquer' and is reflexive.
Après être sorti, je me suis aperçu que j'avais oublié mes clés.
(After going out, I realized that I had forgotten my keys.)
Elle s'est aperçue trop tard de son erreur.
(She realized her mistake too late.)
Nous nous sommes rapidement aperçus du malentendu entre nous.
(We quickly became aware of the misunderstanding between us.)

Summary

'Remarquer' is often used for more deliberate observations and can imply commenting, while 's'apercevoir' indicates a personal realization about something initially unnoticed. Understanding the context and subtlety of awareness involved will guide the appropriate choice between these terms.