What I understand from a machine translation of that article is that the root problem is that Free have decided to run their network with only a single transit provider. That transit provider is Cogent.
As a tunnelbroker.net user you also only have a single transit provider. That transit provider is Hurricane Electric.
Cogent and Hurricane Electric aren't able to reach an agreement. From the information I have read on the subject it sounds like Cogent takes most of the blame for that dispute. You are welcome to take that last statement with a grain of salt, after all this forum might be skewed slightly in the favor of Hurricane Electric.
If you as a tunnelbroker.net user want multiple transit providers you would have to get your own addresses and BGP tunnels through different providers. I know of three providers who offer BGP tunnels. Doing BGP announcements with the addresses you received through a standard tunnelbroker.net tunnel would as far as I recall be a violation of the terms of service.
Until recently there was a direct peering between Free and Hurricane Electric, which is why the connection used to work. But for reasons which are not clear Free shut down that peering.