Well, we got our basic labour laws already with the Civil Code, adopted on 18.08.1896 ...
And since 1927 we've got special Labour Courts (up to the Federal Labour Court), which were before branches of 'normal' courts.
And because of the German membership in the European Union (EU), labour law is strongly influenced by EU legislation and case law.
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Probation time in Germany:
Probation is regulated in the Civil Code:
When concluding a labour contract the parties often agree on a probationary time of up to 6 months. During this period, the employee can be dismissed with notice of only 2 weeks (sec. 622 $ 3 Civil Code). Alternatively, the parties may enter the employment relationship by agreeing on a contract that is limited up to 6 months. The necessity of mutual testing is a justifying reason of the above-mentioned sec. 14 § 1.
National Labour Law Profile: Federal Republic of Germany - although not updated during the last years, that site seems to show the actual law (as far as I can remember :wink: )