Provisions for Retirement Benefit Obligations - Breakdown of actuarial gains and losses recognized in comprehensive income (Details) - EUR (€) € in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Provisions for Retirement Benefit Obligations
Demographic changes	€ (27)	€ 14	€ 32
Changes in actuarial assumptions	109	(63)	(129)
Total	€ 82	€ (49)	€ (96)
Discount rate	1.00%	0.35%	0.70%

The amount of other comprehensive income, net of tax, related to gains (losses) on remeasurements of defined benefit plans, which comprise actuarial gains and losses; the return on plan assets, excluding amounts included in net interest on the net defined benefit liability (asset); and any change in the effect of the asset ceiling, excluding amounts included in net interest on the net defined benefit liability (asset). [Refer: Other comprehensive income; Defined benefit plans [member]; Plan assets [member]; Net defined benefit liability (asset)] [Contrast: Decrease (increase) in net defined benefit liability (asset) resulting from gain (loss) on remeasurement in other comprehensive income]

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