Pat_154: we have done all the Christmas Market cruises over the years and the Rhine was our favorite. We went after Dec 2nd but I hear they begin to open late November. The atmosphere is wonderful and the markets are varied and colorful. Our Christmas tree is full of Old World ornaments and memories.
Altho I enjoyed the Seine Christmas cruise, I noticed the France is not a particularly religious country and their Christmas Markets are not rife with Christmas ornaments etc. They usually have lots of food and drink (nothing wrong with that) and clothing. Most of the atmosphere is the colorful lights and bustling crowds. A ferris wheel right in front of the Rouen Cathedral really puzzled me. We did attend a High Mass at the Rouen Cathedral which was a special event for us.
I found the people in Germany to be more in tune with the religious side of Christmas especially for the children. In Cologne at High Noon Mass, young families were pouring in with little children to attend and to hear their spectacular organ music. Whatever one you chose, I think you will enjoy the Holiday atmosphere wherever you go. We brought our Christmas Spirit with us and absorbed all of them.