The disk image of l'Affaire from PassionMSX doesn't work on many WD2793 based machines in openMSX (e.g. a Philips NMS 8250). It is said to be running fine on a real 8250. See http://www.msx.org/forum/msx-talk/openmsx/problems-laffaire
Max Iwamoto wrote: " If you start openMSX debugger and write 00h into 7FF8h, the game will continue loading and start. "
I tried with openMSX 0.8.2 and with that version it runs. (I don't have good means to bisect right now.)
I suggest to verify that it indeed works on a real 8250 and then ask an FDC expert to investigate further (Wouter :)).
Fixed by Wouter in 2d13bf46fe6835335e5f8eba525875555c4b7ca5 thanks!