Rechercher vs. chercher

The French words 'rechercher' and 'chercher' both imply a searching action but have subtle differences in usage and connotation. Understanding these can help learners of the French language use them appropriately.

Rechercher

'Rechercher' often implies a more intense, profound, or systematic search than 'chercher'. It can be used for searching for something with high precision or for academic research.
Il est en train de rechercher un remède contre la maladie.
(He is researching a cure for the disease.)
Je recherche un livre très rare.
(I am looking for a very rare book.)
La police recherche activement le suspect.
(The police are actively searching for the suspect.)

Chercher

'Chercher' can be used in a more general sense to indicate looking for or trying to find someone or something without the depth or intensity implicit in 'rechercher'.
Je cherche mes clés, tu les as vues ?
(I am looking for my keys, have you seen them?)
Cherche bien dans ta poche, peut-être que ton billet est .
(Have a good look in your pocket; maybe your ticket is there.)
Elle cherche du travail depuis un mois.
(She has been looking for a job for a month.)

Summary

'Rechercher' and 'chercher' both involve searching, but 'rechercher' savors a more comprehensive and detailed endeavor, typically used when referring to more serious or scholarly searches. In contrast, 'chercher' usually refers to more general acts of looking for something without the intricacy that 'rechercher' conveys.