The German Foodstuffs and Consumer Goods (LMBG)
The LMBG is the foundation of the regulatory agency thereby it can discharges its control function. The purpose of the food supervision among others is to control the proper contact with jewellery (§5, LMBG). According to this it reads as in subparagraph 6: "Consumer goods for the purpose of this law [...] are objects, which aren´t meant to contacted with the human body only temporarily [...]“. In exhibit 1 it reads that for the "production or treatment of ear studs or similar products, here piercing jewellery, which are meant for remain in the human body up to the healing of the sore canaliculus", nickel is forbidden. In the practice it means that the amount of nickel mustn´t above 0.05%.
The German Civil Code (BGB)
The BGB among others defines the legal capacity. Arising from the articles §106, §107 and §113 minors are only limited competent. Thats why by pierce of under 18-year-old persons an approval of the legal guardian must be available. Further the legal guardians can enter an objection and cancel the contract, which the teenager had concluded.