Very often, the workplace is designed to be a fortress against break-ins, with badges to access each room, shredders to destroy sensitive documents without leaving traces, and firewalls to limit the risk of computer hacking.
When you work from home, it's harder to set up the same level of protection. Who hasn't left a document containing customer information lying around in an unlocked room? Who has never forwarded an email to their private, unsecured email inbox?
These are typical examples of what should be avoided. Again, you are subject to the same rules as if you were working on your company premises. If it is forbidden to use a private mailbox in your company, you must impose the same rigour at home. If, on site, you are asked to store your documents in a locked cupboard, you must imperatively store them in a place that is also inaccessible at home. If your company has a shredder, you should not throw your confidential documents in the trash, but wait until you return to your office to destroy them.
Similarly, your employer must provide you with a VPN (a system allowing you to connect to the company's computer network) so that your data has the same level of computer security as it would normally have.
If all these rules are respected, but a hacking or theft of a document still takes place, the liability lies with the employer.
Just make sure that you inform your employer beforehand of the need for teleworking.