@maartje the German press release has a nice map: https://www.deutschebahn.com/de/presse/pressestart_zentrales_uebersicht/Mehr-Nachtzuege-mehr-Verbindungen-mehr-Komfort-DB-und-OeBB-bauen-grenzueberschreitenden-Verkehr-aus-11320956

Splitting the Paris and Brussels carriages in Mannheim is a bit of a diversion, but as long as the departure and arrival times are alright that doesn't have to matter really.