Rick's France book has a very good chapter on Lyon, laying out most of the things of interest to visitors. The only thing I did that he did not describe was the Parc de la Tête d'or, a very nice city park, but that may not be so interesting in February. On a nice day, it seemed half the city is there; there was a great mix of people, and it was very enjoyable.
If you really have seven nights, you'll definitely have time for day trips; even seeing "everything," you'd probably only need 4 days for Lyon. For trains to many other cities, including Dijon, Beaune, and Paris, you'll want advance purchase discount tickets, as last minute tickets can be very expensive. However, these advance tickets will be non-refundable and non-changeable. I haven't investigated closer daytrips, but I know one is Vienne, with Roman ruins.