Facts: A-GmbH gives its employees the ’urgent recommendation’ not to incur any additional material costs during maintenance work. During the repair of a machine, B, a fitter from A-GmbH, then installs a component that is 10 percent undersized according to its specification. However, B thinks that the customer only uses the machine once a month anyway and that nothing will happen. In reality, however, a fire breaks out during operation of the machine, killing two employees and causing property damage of EUR 10 million. In addition, the customer is no longer able to fulfill a contract and loses a further EUR 5 million as a result.

Question: Who is liable for the damage? What is the degree of fault?