Other income and expenses - Other operating expenses (Details) - EUR (€) € in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Other income and expenses
Currency losses	€ 1	€ 34
Total other operating expenses	€ 1	€ 34	€ 86

The amount of expenses that the entity does not separately disclose in the same statement or note when the entity uses the 'function of expense' form for its analysis of expenses.

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