Are strict migration proposals by Bavaria's CSU party legal?

Ahead of Germany's election in February, Bavaria's conservative CSU party has said it will only accept migrants who pay their own way. Experts see their policy proposals as electioneering and potentially illegal.

source https://www.dw.com/en/are-strict-migration-proposals-by-bavaria-s-csu-party-legal/a-71215976?maca=en-rss-en-ger-1023-rdf