Further legal bases

EU law

EUV 2007/2009 Treaty on European Union
Art. 2 TEU
The values on which the Union is founded are respect for human dignity, freedom, democracy, equality, the rule of law and respect for human rights, including the rights of persons belonging to minorities. These values are common to all Member States in a society characterised by pluralism, non-discrimination, tolerance, justice, solidarity and equality between men and women.

Art. 3 Para. 3
The Union shall establish an internal market. It shall work towards the sustainable development of Europe based on balanced economic growth and price stability, a highly competitive social market economy aimed at full employment and social progress, and a high level of environmental protection and improvement of the quality of the environment. It shall promote scientific and technical progress.
It shall combat social exclusion and discrimination and promote social justice and protection, equality between men and women, solidarity between generations and the protection of the rights of the child (...).
 

TFEU 2007/2009 Treaty on the Functioning of the European Union 

Art. 8
In all its activities, the Union shall aim to eradicate inequalities and to promote equality between men and women. 
Art. 10
In defining and implementing its policies and actions, the Union shall aim to combat discrimination on the grounds of sex ...
Art. 157 (4)
With regard to guaranteeing full equality in practice between men and women in working life, the principle of equal treatment shall not prevent any Member States from maintaining or adopting measures providing for special advantages in order to make it easier for the under-represented sex or to pursue a vocational activity or to prevent or compensate for disadvantages in professional careers.
Charter of Fundamental Rights of the European Union 2000/2009 
Art. 23
Equality between men and women shall be ensured in all areas, including employment, work and pay.
The principle of equality shall not prevent the maintenance or introduction of special advantages for the under-represented sex.
Directive 2000/78 / EC of November 27, 2000 for establishing a general framework for the implementation of equal treatment in employment and occupation
Art. 7 Para. 1

The principle of equal treatment shall not prevent any Member State from maintaining or introducing specific measures to prevent or compensate for disadvantages linked to any of the grounds of discrimination referred to in Article 1, in order to ensure full equality in professional life.

German Constitutional Law

Basic Law

Art. 3 Para. 2
Men and women shall have equal rights. The state shall promote the actual implementation of equality between men and women and shall work towards the elimination of existing disadvantages.
Bavarian Constitution 
Art. 118 para. 2
Men and women shall have equal rights. The state shall promote the actual implementation of equality between men and women and shall work towards the elimination of existing disadvantages.

German individual legislation

General Equal Treatment Act

§ 5
Notwithstanding the grounds specified in §§ 8 to 10 and in § 20, different treatment is also permissible if suitable and appropriate measures are to be taken to prevent or compensate for existing disadvantages due to a reason specified in § 1.