Hello,
With a french residency permit, that i assume you have as a student, you may travel in all Schengen countries visa free.
The United Kingdom is not part of Schengen and has its own visa regulations, which you will have to follow in order to travel to that country.
It is my understanding the mexican nationals require a UK visa to travel to the UK.
Regards.
Martin
MediaVisa.net
Schengen travel insurance at the lowest price