In the given event log, several attributes could be considered sensitive for fairness. These attributes may influence the decision-making process in a way that could lead to discrimination or biased outcomes. The sensitive attributes are:

1. `case:citizen`: This attribute indicates whether the individual is a citizen or not. Discrimination based on citizenship status could lead to unfair treatment.
2. `case:gender`: This attribute indicates the gender of the individual. Discrimination based on gender could lead to unfair treatment.
3. `case:german speaking`: This attribute indicates whether the individual speaks German or not. Discrimination based on language skills could lead to unfair treatment.

It's important to ensure that these sensitive attributes are not used in a way that could lead to biased decision-making in the loan application process. Fairness can be ensured by treating all applicants equally, irrespective of their citizenship, gender, or language skills.