Police allege Gauthier drove up on the sidewalk at the corner of St-Laurent and Ontario streets and hit two young men with his taxi after they tried to flee without paying their fare.
Both men, aged 18 and 20, suffered head injuries but are expected to survive.
Gauthier is facing one count of dangerous driving, and two counts each of dangerous driving causing bodily harm, criminal negligence and assault with a weapon.
Accused and his mother testify
A bail hearing began Wednesday morning with the defence calling two witnesses -- Gauthier himself and his elderly mother.
Their testimony is protected by a publication ban.
Gauthier wiped away tears and buried his head in his hands during his mother's testimony.
The hearing is expected to continue Wednesday afternoon before Quebec Court Judge Marie Josee Di Lallo.