Francophonie· medium
mettre la puce à l'oreille
“to put the flea in the ear”
Meaning
to make someone suspicious
Explanation
It means to trigger doubt or suspicion in someone's mind.
Example
Son changement de version m'a mis la puce à l'oreille.
His change of story made me suspicious.
Origin
It is linked to the irritating image of a flea in the ear that keeps someone awake and restless, then by extension mentally uneasy.
Source