By Juliette Jabkhiro BOBIGNY, France (Reuters) – Three French policemen went on trial on Tuesday accused of deliberately using excessive force in the arrest of a young Black man that left him disabled and sparked protests. The arrest of Theodore Luhaka in 2017, when he was 22, was one of several cases in recent years that put the spotlight on rights groups’ accusations of systemic racism in the police and led to street protests in Paris and some of its suburbs. One of the policemen, Marc-Antoine Castelain, beat Luhaka with a collapsible baton during the arrest in the suburb of Aulnay-sous-Bois…