Our provider OVH confirmed us the problem on their side:
There was an issue with importants links between Gravelines and Roubaix.
Traffic pathing through and coming from North North-Est of Europe could have been impacted.
The cut was generated by the automatic switching on provider’s backup links
Source: http://travaux.ovh.net/?do=details&id=41714&PHPSESSID=19e7d98b38cfe68fec43510fbb0bab6f