As far as I understand it, in France there are something like three "levels" of convictions, the lowest ones are not kept on record, the middle level convictions are kept for a short time (three years?) and the highest level ones are kept forever.
I think the judge has some leeway to decide the level of his decision.
Also, only some government organisations and such have access to the middle level records, but a regular employer can't get them. Or they can't after a number of years, or something like that. It's been a while since I haven't checked the details of the procedure.
Also, nobody can get them behind your back, the process is they ask you for them, give you a certificate that they are allowed to if they are asking for the higher level records, and you ask for the records yourself providing the certificate and some id, etc. It's a bit heavy and lengthy, but it means you always know who has access to your records, you also know exactly what they see, and the administration knows who asks for it so they can check if there's too much abuse.
I'm not sure about the details, but basically there are both different access levels and different keeping duration. I think it's a good system.