Simple and literal:
* Un peu bleu: This is the most straightforward translation, literally meaning "a little blue".
* Bleu clair: This translates to "light blue" and can be used if you're referring to a light shade of blue.
More nuanced:
* Un peu triste: This means "a little sad" and could be used if you're talking about someone feeling a bit down.
* Un peu déprimé: This translates to "a little depressed" and is a stronger expression of sadness than "un peu triste".
* Un peu mélancolique: This means "a little melancholic" and conveys a sense of gentle sadness or longing.
Contextual:
* Une touche de bleu: This means "a touch of blue" and can be used when describing a color scheme or painting.
* Un peu de bleu dans le ciel: This means "a little blue in the sky" and is a specific example of the color blue.
Ultimately, the best way to say "a little blue" in French depends on the specific situation. Consider the context and the emotion you want to convey when choosing the right phrase.