There are some rows in the frwiki_p database containing text encoded in latin1. This is probably not a good thing. Consider https://fr.wikipedia.org/w/index.php?title=France&diff=prev&oldid=498177&diffonly=1 ; the edit summary does not appear, and yet:
```
MariaDB [frwiki_p]> select rev_comment from revision where rev_id=498177;
+-----------------------------------------+
| rev_comment |
+-----------------------------------------+
| HasharBot - [[Cat�gorie:Pays d'Europe]] |
+-----------------------------------------+
1 row in set (0.00 sec)
```
Which appears to be b"HasharBot - [[Cat\xe9gorie:Pays d'Europe]]" in Python 3. The offending character is "é", which is encoded in latin1 instead of utf8 (b"HasharBot - [[Cat\xc3\xa9gorie:Pays d'Europe]]").
Please do the needful and proceed with the process of fixing this.