With the GDPR becoming applicable on 25 May 2018 and the new Belgian Data Protection Act of 30 July 2018 entering into force on 5 September 2019, more severe administrative fines and criminal sanctions were introduced in conjunction with several data protection obligations. According to European and national law, there can be no retroactive application of more severe penalties. The European Court of Human Rights has developed some criteria in its jurisprudence to assess whether this principle of non-retroactivity also applies to administrative fines, being (i) the legal qualification of the infringement in national law, (ii) the nature of the infringement and (iii) the severity of the penalty. Following this test, it appears that the administrative fines under the GDPR fall within the scope of this principle of non-retroactivity.
What does this mean in practice?
For infringements that existed only before 25 May 2018, the new sanctions may not be imposed. For infringements that existed only after 25 May 2018, the new sanctions may be imposed. The difficulty lies with infringements that existed both before and after 25 May 2018.
For infringements that existed before and after 25 May 2018, a distinction must be made between criminal sanctions and administrative fines. For criminal sanctions, the infringement will most likely be considered as a whole by using typical mechanisms of criminal law such as “eenheid van opzet / unité d'intention” and “voortdurend misdrijf / infraction continue”. In this respect Article 65 of the Belgian Criminal Code states that: “where one and the same act gives rise to several offences or where several offences which are the successive and continuous execution of the same criminal intention are simultaneously submitted to the same criminal court, only the most serious penalty shall be imposed”. Consequently, the new sanctions will probably be applied to the whole of the infringement.
For administrative fines, the situation is more unclear. The Belgian Constitutional Court has previously ruled that it is not discriminatory that these mechanisms of criminal law do not apply to administrative fines. Article 82, §3 GDPR states that: “if a controller or processor intentionally or negligently, for the same or linked processing operations, infringes several provisions of this Regulation, the total amount of the administrative fine shall not exceed the amount specified for the gravest infringement”. Other than the Article 65 of the Belgian Criminal Code as referred to above, this article is limited to infringements of the GPDR itself and does not explicitly refer to any succession or continuity over time. However, Data Protection Authorities have a lot of leeway and can apply various criteria to ensure reasonableness when imposing administrative fines, amongst which the duration of the infringement, so that de facto they could probably apply the same mechanisms.
 See Article 7 of the European Convention on Human Rights and Article 2 of the Belgian Criminal Code.