Hi!
The AND logic for taxonomy terms connected to post types means that ‘any of the taxonomy term names contain every search phrase’, as each taxonomy term is a separate object related to the post type.
In this case ‘Avis red’ would only match if there was a taxonomy term connected to the attachment that has both ‘Avis’ and ‘red’ in their title. To match either-or, I recommend rather using the ‘OR’ logic instead.