Most migrants must be long-term residents for 8 years before they are eligible for German citizenship. Their children and grandchildren must fulfil additional requirements before becoming citizens of their country of birth. To naturalise, applicants must meet conditions that are the third least favourable of the 28 MIPEX countries after AT and DK. They must pass a language exam, integration test and criminal records check, and must prove that they have sufficient income. Their applications can still be rejected, or their nationality later withdrawn, regardless of many personal circumstances or how long they have been a citizen. A 24 May 2006 Federal Constitutional Court decision required withdrawals to have certain time limits though their length is still to be defined. Germany only allows dual nationality for naturalising migrants based on exceptions and for the children of foreigners under heavy conditions.
