Just over two-thirds of eligible voters in Germany have a long-standing affiliation with a political party. This applies to almost all age groups. Only people aged 70 and over are more likely to have a party affiliation than younger people. However, there are significant differences between age groups in terms of which party they feel affiliated with. Whilst people aged 70 and over are more likely to feel affiliated with the CDU/CSU and SPD than with any other parties, those under 30 are more likely to report an affiliation with the Left Party, the Greens or the AfD than with the CDU/CSU or SPD.
You can read more about party affiliation and its relationship to multiple party affinities in the study “A Comparison of Party Affiliation and Party Affinity” (only in German).