I will name several German policies that make impression the government is striving to prevent inter-ethnic mixing:
There are lists of permitted names for each ethnicity. One cannot take or give their children a name of their wish which is not listed as permitted.
All people have their religion registered and the believers have to belong to a church or another religious organization.
There is a church tax, famously imposed on Christians and Jews but not on Muslims which discourages them from converting.
When immigrating to Germany (for instance as a Jewish refugee from the former USSR), atheists are not allowed. Each ethnic Jew is required to get registered at a synagoge. Christian Jews are also not allowed.
Muslim refugees are not allowed to convert from Islam into Christianity in refugee camps, if they violate, they are deported back to their countries.
To emigrate to Germany one has to prove either German or Jewish blood. Only pre-1991 papers are accepted because some post-Soviet countries allow to change the registered ethnicity according the self-identification. This reminds Nazi Germany where one had to prove their German blood with pre-1871 papers.
Why such policies are conducted?