Hi,
This is a known issue registered as GWS-271 : HTTP client and server API should handle UTF-8 in URL encoding and decoding.
Current implementation considers only ASCII characters during URL encoding and decoding. All characters not in the ASCII table will be escaped with %XX. I'm sorry, but if the client encodes the URL in UTF-8 first, Genero will not be able to URL decode it properly on server side because the %XX characters will simply by converted to locale charset.
This will be fixed for Genero V3 as API will have to be updated to handle potential charset conversion error.
Regards,
Frank