From Florence Gaub and Julia Lisiecka’s study, published by the EU Institute for Security Studies in April 2017:
Continuing the trend, Mohamed Lahouaiej-Bouhlel, the driver of the lorry in the Nice attack, had been sentenced only four months prior to the atrocity to a six month suspended prison sentence for assaulting a motorist with an improvised weapon. The Berlin Christmas market attacker, Anis Amri, also had a criminal past: before arriving in Germany, he was wanted by Tunisian authorities for the theft of a truck and sentenced in absentia to five years in prison, and was also jailed in Italy for arson. More recently, the perpetrator of the attack in Westminster, Khalid Masood, was also known to the UK police due to a colourful criminal history including grievous bodily harm, possession of a knife and various public order offences.
Study in full here.