12 day Trip: Paris to Normandy to Munich

Fly into Paris take the train directly to Bayeux
Bayeux 3 nights
Train to Paris
Paris 5 nights
Train to Munich
Munich 4 nights

Visiting the Eagles Nest, near Berchtesgaden, from Munich would be a very long day trip. Just getting to Berchtesgaden would be 2 1/2hrs by train or 1 1/2 hrs by car (each way), then the bus up to the Eagles Nest (or the much longer hike to the top from the parking lot.). Roughly 4-6 hours spent on transportation alone. If you want to see it as well as spend time in the surrounding area, I'd recommend staying in Berchtesgaden (or Salzburg) rather than Munich. But you would want to be back in Munich the night before your flight home.

Thank you for the advice. We just booked our hotels and followed your suggestions. We are going to stay in Bayeux for a couple of nights and Berchtesgaden for a couple of nights. Any tips on navigating the trains from Paris to Berchtesgaden is appreciated. What company should I purchase my train tickets?

Book directly with the train company you will be riding. SNCF from Bayeux to Paris. Then Deutsche Bahn. https://int.bahn.de/en Don't use a 3rd party ticket seller.
A quick look at a random day next month shows a 9 1/2+ hour trip with 2 or 3 connections from Paris.
If you are unfamiliar with European trains, the Man in Seat 61 website can be a wealth of valuable information.

Don't miss the Bayeux Tapestry, 900 years old that tells the story of the Norman conquest of England. You will be in Bayeux, it is amazing.

It's best to buy the train tickets from the national train company of the country of departure or arrival. In your case I would look first at Germany's bahn.com.

Also note that there are 10 or so direct flights everyday from Paris to Munich, costing about the same or less than the train. Of course from there you would need to take the train to Bertchesgaden. And transfer time to the airport in Paris is not inconsequential.

Also note that tourist hot spot Salzburg Austria is closer to B'gaden the Munich. It is not unreasonable to stay in Salzburg and do a day trip to the Eagle's Nest. There might even be a guided tour out of Salzburg.

thank you everyone for your responses. I have some more questions that I'm hoping you all can help me with.
1) For the train from Paris to Bayeux, what web site should I use to purchase the train ticket, or is this a ticket that I should just wait until the day of travel to purchase at the station?
2) My plan is to get a train ticket from Paris to Berchengaden. I was thinking of going to the website mentioned here by RS (bd?) and I noticed that there's generally 3 stops with one being 10 minutes in Stuttgart Hbf. I have heard that it's generally across the platform. Should I assume that or is that risky to only have 10 minutes?
Thank you for all your help. I really do appreciate it!

The French rail line is SNCF. Their website is here: https://www.sncf-connect.com/app/en-en/home/search/od
The German rail line is Deutche Bahn. Their website: https://int.bahn.de/en

10 minutes in Stuttgart should be fine. Just make sure you've gathered all your belongings and are standing near the door when the train stops.

I like using the train, but there's no way I'd try and go from Bayeux (or Paris) to B'gaden by train in one day. it's a waste of time if you're planning to spend time in either Paris or Munich. Plan to travel from Paris to Munich, preferably by air. Cost is about the same and it will save you half a day. For the Eagles Nest book a tour out of Salzburg and plan to travel there from Munich via train and overnight there.

Travel time cuts into your vacation. Always minimize that.

The tour from Salzburg is 95 Euro and includes transport.

You can travel from Munich to Salzburg via train (in half the time you would take getting B'gaden) using the Bayern pass for 22-30 Euro.

Paris to Munich by air is less than 2 hours and @ 60-100 euro. it's a direct flight and no standing around or changing trains.

Stay at the Boutique Hotel am Dom in Salzburg.