Alsace Region - Via Paris or Frankfurt

Where will you be going after you leave Alsace?

Anticipate no problems driving across the border; at least I recall none when we met some friends from the U.S. in Strasbourg a few years ago and drove with them over to Freiburg before heading south to Chamonix.

Of course, that was our own car and not a rental, but with a rental the main issue might be what happens to it once you're finished in Alsace; hence my leading question.

There is absolutely nothing preventing you from taking a train from Frankfurt airport to Alsace. There is also bus service from the airport to Strasbourg. You could also look at using Air France rail & fly ticket (if that is the airline you are looking at to Paris), or with Lufthansa and many other airlines to Frankfurt getting a Rail&Fly ticket. That way you can take any train within 24 hours of landing to you destination.

Either way will work. I felt it made the most sense to fly into Paris, then train to the area. For me it was Auxerre, pick up a car, drive south through Burgundy then over to Alsace drive south to north, drop the car in Strasbourg, train to Reims for a stop before another train back to Paris.

I think you should consider the time and cost of each way, then pick the one that works best for you. You won't have an issue with the rental at the border. On the loop mentioned above, I ended up with some spare days so I crossed to Freiburg, then drove up to Heidelburg, before going back to Strasbourg and catching my train to Reims. There was no issue at all crossing the border with a rental. You really wouldn't even know you had crossed a border.

Whatever airport we fly into (Paris or Frankfurt) is the airport we would fly out from for our travel back home.

See my Colmar post for a great place to stay in Alsace.

https://community.ricksteves.com/travel-forum/france-reviews/going-to-colmar-i-have-a-lodging-recommendation-for-you

Personally, I would fly in and out of Frankfurt. Flying back to Detroit? - direct flights. If not, Aer Lingus from Toronto is usually a reasonably priced flight, at times on the very low side. Short change time in Dublin.

If you arrive in Frankfurt fairly early in the day from Oslo, rent a car and catch Wissembourg on the way down , it's a pretty town often off the Alsace itinerary. A direct drive to the Colmar area from FRA will be about 3 ½ hours. As well as the most commonly visited Alsace villages, I highly recommend Staufen and Gengenbach on the German side. Lovely, moderately easy hiking in the area.