I'll do it step by step just so I can remember ha.
Downloaded Safari and Hotspot Shield.
Connected Hotspot Shield and selected virtual option United States.
Using Safari go to
http://www.grandstade-lillemetropole.com/
Top right it has 'MON COMPTE'. put email address and create a password in these 2 boxes and click 'créer un compte.
On the next page you have to put in: civilité (title), Nom (surname), prenom (first name) and email address, i left no Abonné blank.
On the next page its address dob etc to fill in and on the right confirm password twice. Pays being country and Royaume-uni is an option, up to you if you have a French address etc. Then click the bottom right red button to complete the registration. I think I may have gotten an error message, but I also got a confirming email straight away!
I opened another browser, went to the same site and then went to buy tickets (before logging in) selected my seats and had to then log in, re-confirm password twice and it took me to the payment screen.
TURN OFF HOTSPOT SHIELD before you confirm this. I tried it once and it didn't work, it just brought up a blank page, had to do it again, the same seats were available to I booked those, turned it off and it worked.
If you have an android or iphone, download the world lens app, and download French - English it helps with translating text using the camera, doesn't use internet at all. Was handy for some phrases