After a burglary, the model conditions (VHB 2010) require a list of the missing items — without delay, for the insurer and for the police. Breaching such a duty through gross negligence can lead to a reduced payout.
What counts are the conditions of your own policy.
link Source: GDV model conditions for home contents insurance (VHB 2010), part B § 8; § 28 VVG.