It seems that Filezilla does not handle special characters correctly in a automatic mode. When we talk about special characters, we talk about the "UTF-8" encoding which is the most famous.
Although the FTP protocol was invented at a time when special characters did not exist yet, today, the client and the FTP server are able to handle special characters if they are both well configured.
When you transfer maps with special characters in the name with Filezilla, if the client is not properly configured, you may end up in a situation like this :
File names does not match so it will be impossible to delete them.
To avoid the problem describe above, it is necessary to force Filezilla to use UTF-8 (the FTP server does handle it but Filezilla, in the automatic mode does not).
To configure Filezilla, go on the site Manager
Create a new site
And configure the new site by giving it a name filling in the form about the login information
Then, go to the "charset" tab and force the "UTF-8" charset
Click "OK" ou "Connect". You should now see the right file names on the remote server
To connect later, use the Filezilla site manager again.