Is there any service on 1st class on international trains?

If you travel by 1st class to Germany, you will have more legroom and wider seats. Usually, there is also more quiet on 1st class. 
The train offers free newspapers, and with your 1st class DSB ticket, you can get a free cup of coffee or tea from DSB 7-Eleven at the station. 
A 1st class ticket also gives access to DSB1’ Lounges at Aarhus, Odense and Copenhagen Central Station. With a 1st class ticket, you also have access to DB Lounge at the large German stations such as Hamburg, Berlin, Bremen, Cologne, Frankfurt and Munich.