How to send messages with special characters ?

[Fripouney]

Hi !

I'm very new to node.js and tmi.js so this might look like a stupid question
I was wondering how I could send messages with special characters on twitch chat.
When I simply use client.say(channel, "this message has a special character é"), the "é" will not display at all in chat. Since I need to send messages in French, this is quite problematic.
I'm guessing there is some kind of encoding problem there, but could not find a way to fix it.

Does anybody know how I could fix this ? Any help would be very appreciated :)