关于在英国购买法国火车票的问题?谢谢

第一次在网上购买了法国的火车票，有关取票时间的问题？　是不是也和英国一样，只要出发前取票就可以了。因为我看到有个 FARE CONDITION class seat. Tickets must be purchased at least 14 days before travel. Tickets must be issued immediately. | Non exchangeable and non refundable. (Fare Name): Std Class Prems. 这里的提前１４天购买什么什么意思呢？　　谢谢！！