I worked as a temp for france tax collection before my degree (circa 2012-2013l.

People were registered in 3 different database, each of them independent, each of them on a different software (one aspnet/vbnet you connected through a browser, one very, very old, clearly IBM software, and the third one was probably as old as IBM, if not older, but looked like a minitel portage on windows). All the relevant data were dispersed on those three (a fourth one existed but only authorised people could use it because you had bank account numbers on it). Also, only the Vbnet software allowed copy paste, which means that to find someone, you had to file the tax number+surname 3 time, without making any mistake.

I wonder which one was broken into. No bank details, so it probably was one I had access to as a temp. Maybe they upgraded their software though, because if I remember correctly only they all worked on the local network (not sure about the aspnet one).