Probably Switzerland - init7 has it in its offer: https://www.init7.net/en/internet/fiber7/

The price is the same as for 1Gbps and 10Gbps (~60USD/month) - though the initial setup price differs: ~300USD for 25Gb/s vs <100USD for 1Gbps

The actual speed within network is indeed 25Gb/s to some fellow users running speedtest.net servers. Inside Switzerland it's maybe ~15Gb/s to some well connected servers in the area of Zurich, and ~10Gb/s across EU. Tested with speedtest.net and iperf.

I think in the EU the limit is sometimes not Init7 but the Speedtest.net servers. I ran a test to many of them and did get above 10Gbps but only to eu-25g.ookla.tierservers.com, which clearly has a 25Gbps NIC.

A bunch of other Speedtest.net servers were located in Amsterdam and took a very similar route via Cogent but none of the others broke the 10Gbps barrier.

It is for sure often Init7 though. Those peering relationships it built up have become a bit of a weakness because they're usually limited to a 10Gbps port.

Literally this announcement is saying where. It’s not just the convention center, it’s the whole service region, the convention center is just first.

As another commenter said, Switzerland. There's no change to the monthly price, just some one-off charges so I decided what the heck.