You can report the loss

• at any identity card authority, usually the local citizens' registration office, or
• at any police station.

If necessary, you can arrange for the online ID card function to be blocked by the issuing authority or by calling the blocking hotline.

In the case of blocking by telephone, identification is required via the blocking password (was sent with the transport PIN and the PUK by Bundesdruckerei).

In addition, if necessary, you can have the electronic signature blocked by the provider who purchased the signature certificate.

It is important to note that no one can read your data without your PIN.The easiest way to block is via the telephone blocking hotline.

You must also apply for a new ID card if you are over 16 and do not have a valid passport document, i.e. a passport or temporary passport. This is possible at the citizens' registration office at your main place of residence. If necessary, a temporary identity card can also be issued.
If you do not apply for your identity card at your main residence, you need an important reason. In addition, a surcharge of EUR 13.00 will be added to the fee. If you contact your chosen Bürgeramt beforehand, you can find out whether and to what extent the Bürgeramt recognizes your reason.
In case you recover your identity card, you must report this personally to your local identity card office. Only when you have officially reported your identity card as "found" will a corresponding entry in the police records be deleted.
Provided you have not applied for a new ID card, you can continue to use your ID card that has been reported as recovered in Germany without restriction until its validity expires.