utf8 characters in cucumber feature file

In my feature file, I have the following line:

When I search with <q=+Brontë> using xml

This blows up with:

incompatible character encodings: UTF-8 and ASCII-8BIT
(Encoding::CompatibilityError)

Is there a trick to getting non-ascii characters in a .feature file?

(I'm pretty sure that my feature file is saved in utf-8).