|Subject: Transport in Berlin and Paris|
I can answer your first two questions :
1._ The 7-day ticket for Berlin works only from Monday to Sunday. You
can buy it the previous Sunday at any metro station or at the special
Berlin Transport Office booths (I think they are called Tickets und
mehr, and there is a handy one outside of the Zoo Bahnhof). You can
pay with Visa card.
2._ The Paris metro carnet. You cannot use 6 tickets to go from zone 1 to zone 6. They are only valid in the zones 1-2 . If you are going further, you need a ticket that cover those zones (I donīt know if you can do as in London, buying an extension for the extra zones. But that can only be done if you have bought a day or a week ticket ...).
Good luck with your approaching vacation, Covadonga Bilbao - Spain