Getting a bike (unpacked) from Paris to Brussels by public transport

bisikletci

Does anyone know of a way to get a bike from Paris to Brussels by public transport without having to take it apart and put it in a bike bag? As far as I understand you have to pack it up for both the Thalys and the Izy train services, and there are essentially no non-express services between the two cities that don't involve changing a million times. Is there a bus firm that will take bikes? Or other options? Grateful for any help.

Thanks.