Left wing back Jonathan Clauss scored once and set up the other two goals as Marseille moved a point ahead of PSG, who host struggling Nice on Saturday.
The home team dominated the opening 35 minutes, penning a sloppy and sluggish Marseille team back.
But the hosts could not take their chances. Nabil Bentaleb was closest when he hammered a shot against the near post.
At the other end, Luis Suarez came nearer to hitting the corner flag than the goal with a sliced shot.
Angers paid the price for wasting opportunities.
Seconds after Adrien Hunou scuffed a shot wide of the Marseille goal from close range, Clauss gave the visitors the lead.
Marseille moved the ball quickly into midfield and Suarez found Clauss surging into space up the left.
The wing-back raced toward the box, then skipped outside a couple of defenders before drilling a left-foot shot off the post and past goalkeeper Yahia Fofana.
Before half time Suarez, unmarked in front of goal, headed wide.
Suarez found the target after 50 minutes. Clauss intercepted a sloppy clearance on the halfway line and charged into the penalty area.
This time he squared to Suarez. The Colombian controlled the ball and smashed it home.
Clauss set up another goal after 59 minutes, picking out Gerson at the far post who placed his shot past Fofana.
The game then reverted to its earlier pattern with Angers creating and wasting chances before Marseille ended the match rolling the ball around at walking pace.
Marseille were weakened by bans. Coach Igor Tudor was banished from the sidelines for accumulating yellow cards and midfielder Nuno Tavares was suspended.