I'm reading a text written in French, and the character is introducing herself to another one. She says her name is Julie Dieudonné-Peyrard, but the other character doesn't understand and asks her to spell it. After spelling, she asks if he did understand, and he answers with "Oh, là, là". What does this expression mean? Is it used in other contexts?
In this context, I guess it means that the other character finds the other's name very complicated. In English it would be something like oh, dear.
This post on lawlessfrench.com has a good explanation of the meaning of oh là là in other cases
The French phrase oh là là isn't so much an expression as an interjection. It can indicate surprise, disappointment, commiseration, distress, annoyance… any moderately strong reaction to something that was just said or done. It can be strengthened with additional là's, always in pairs.