It's the same situation here in Lithuania - various companies have these lockers but it's hit or miss who an international package will be delivered by. Even from Amazon I've had packages delivered by DHL, UPS and regular mail.
The post office will give you a forwarding address (for regular mail) that will end up in the locker of your choosing, but you then have to pay €x/package, and the lockers are usually at post offices, so it's not really worth it.
The post office will give you a forwarding address (for regular mail) that will end up in the locker of your choosing, but you then have to pay €x/package, and the lockers are usually at post offices, so it's not really worth it.