There are weekday night trains that depart at 20:05 and arrive in Munich at 7:10 am.

Check out bahn.de for specific schedules.

There really isn’t a good option for overnight train. All routes involve a connection — who wants to spend 4 hours in a train station between midnight and 4:00 AM? I’d just take a day train or go for a flight — it’s pretty much a toss-up. 6 hours and fares as low as 59 euros by train. Probably nearly 5 hours and about the same cost by plane when you figure in time and cost to get to/from airports (airport transportation leaves from the train station you’d use) and check-in time.

Oldlady – Am I wrong the CNL goes from Paris to Munich?

I checked dates the end of this month. For some reason the CNL does not run weekends in January or any night between January 25 and 31. Bahn.de shows as running almost every day (including weekends) in February. Not sure what the issue is. Looks like this trip is probably in February, so maybe no problem. The CNL mim mentions is a good option if it’s running the night you want to travel.

It is a bit expensive, though.