Another possibility:
trial for petty offense/crime
trial for minor infraction


Diccionario de Terminos Juridicos (Alvarez-Varo/Hughes) has a good discussion on this issue:

First "juicio de falta" is described as a "trial of a summary or minor offence; type of hearing systematically distinguished from the so-called juicio de sumario or procedimiento ordinario."

The authors go on to say that it is the trial of a falta (misdemeanor, summary/minor offense) as opposed to a delito (serious or non-summary offense), and that the main difference of the juicio de faltas is that it is more informal, there is no formal "sumario" and that the basis of prosecution is usually a police report, so each party must produce its own witnesses and evidence.