The ECJ has ruled in the Judgment in Case C‑484/24 In the NTH Haus­tech­nik case of June 18, 2026, it was deci­ded that a natio­nal court Evi­dence con­tai­ning per­so­nal data may be used even if they were obtai­ned by the sub­mit­ting par­ty in vio­la­ti­on of the GDPR. The GDPR does not impo­se a pro­hi­bi­ti­on on the use of such data. Anyo­ne who deci­des on the admis­si­bi­li­ty of evi­dence and eva­lua­tes evi­dence is ful­fil­ling a legal obli­ga­ti­on, which is why Artic­le 6(1)(c) of the GDPR applies. Con­tra­ry to the posi­ti­on of the Fede­ral Labor Court (BAG), Artic­le 17(3)(e) of the GDPR does not con­sti­tu­te a legal basis (it is mere­ly an excep­ti­on to the right to era­su­re). Fur­ther­mo­re, a court is not requi­red to con­duct its own pro­por­tio­na­li­ty assess­ment invol­ving a balan­cing of inte­rests for every instance of data pro­ce­s­sing. It is suf­fi­ci­ent to assess whe­ther the data used is appro­pria­te and rele­vant to the pur­po­se and limi­t­ed to what is necessary.

The fol­lo­wing fin­ding by the Euro­pean Court of Justi­ce is of grea­ter prac­ti­cal relevance:

… it should be noted that, under cer­tain cir­cum­stances, seve­ral alter­na­ti­ve con­di­ti­ons for lawful­ness may app­ly to the same processing.

In other words, seve­ral legal bases may app­ly at the same time. This is not sur­pri­sing in its­elf, but had not been estab­lished by the ECJ until now.

It the­r­e­fo­re remains unclear whe­ther the con­trol­ler can switch to a dif­fe­rent legal basis in the event of a dis­pu­te. One argu­ment against this is that the duty to pro­vi­de infor­ma­ti­on requi­res the legal bases to be spe­ci­fi­ed — this would be under­mi­ned if the con­trol­ler could switch to an unspe­ci­fi­ed legal basis; howe­ver, it is not clear whe­ther such a switch would affect only the duty to pro­vi­de infor­ma­ti­on or would also exclude the other legal bases. In any case, it is advi­sa­ble to list all rele­vant legal bases in the pri­va­cy policy.