Side mission 1
Eliminating the guards who are escorting prisoners.
Side mission 2
Catch up with and kill the guard who's chasing the man.
Speak with the man to receive a mission of killing the officer recruiting new members to the Templar army.
To complete the mission discretely, go round the building from the left, whistle at the nearest enemy and kill him from behind the corner with a hidden blade.
Eliminate the second enemy from the nearby bushes. He will be busy pushing the protestors, so he will barely notice you.
With him dead, stay in the bushes, hold down the Assassins Guild button and choose the "Marksman". Now aim at the target and press the button once again. That way you will order your associate to kill the officer.