This article explains the special terms that must be put into consideration for renewal of both .DE and .EU domain names.
The country code top-level domains .DE and .EU MUST be renewed 5 days before the expiration date.
If the domain is not renewed in time, it is placed into the redemption period at the Registry and stops resolving before the end of the registration period.
If you do not renew it before the expiration date, it must be redeemed. There will be a fee for the redemption.
Please note that the renewals of such TLDs do not happen immediately.
It is possible to get a .DE domain out of redemption within 30 days following the expiration date, while .EU domain names are placed into redemption after the expiry for 30-40 days.