The second is much further east, but is still within the same district. The first symbol is east and a bit south of the starting point and may be around a group of people talking to each other. Climb up to the top of the northern entrance to find it. The Taurus puzzle actually has four symbols, and the last one is at the northern face of École Militaire, directly south of the tree. The second symbol is at ground level at le Champ de Mars, which is a bit to the east, and the third symbol is directly south of there on one of the wooden structures surrounding the large tree. The first symbol is very, very close to where the start is, and is on a strange wooden contraption on the water a few feet to the north. The third symbol is on the bridge Pont de la Concorde / Révolution, which is east of the viewpoint for the Saint-Thomas-d'Aquin District and west of the Tuileries District. The second is in the courtyard of Palais-Royal, to the northeast, and is on a field of grass. The first symbol can be found at the Louvre on the northern tower and is somewhat below the Nomad Point that shows up there. The final symbol is also on the Notre Dame, and is on the west side among the large arches between the front and middle of the building. The second symbol is on the flowery symbol above the large front doors of the Notre Dame, one district south from here. The first riddle's solution is directly north, in the middle of the clock on the southeast corner of the Palais de Justice. You can find the last symbol on that bridge. Across the gate is a bridge over a river, which is a bit hard to make out since both are blue on the map. Look for a broken-down water wheel and find the symbol on some rocks. It'll be north of the gate with two visibly large towers on the map. The second symbol is on the west side of the Saint-Lambert District to the west.
Per the riddle's obvious first line, go to the front of the Palais Bourbon and climb to the top of the archway in front of the courtyard. The final symbol is at the very northern tip of the island in the middle of Paris, also known as Pont Neuf, and is on the base of the statue there. The second symbol is on the building with two towers directly east (across the street) from the social club in the Palais de Justice District, north of the first symbol's district. The first symbol for the Mars puzzle is in the graveyard south of the starting point. You should really consider using the ropes to get to the tower more easily so you don't have to actually do any slinking around.
The last symbol is on the tower in the middle of the hedge maze east from here. Then locate the building with a tower just a wee bit southeast from here, near a shop, and you'll find the second symbol on the east side of the building after a short climb up to a flat area. Start the riddle, then drop to the south and look on the statue there for the first symbol. Fast travel to the Vendôme District's viewpoint and drop to the roof of the Halle aux Blés, then look at the viewpoint's tower structure for the final symbol. The second symbol isn't at a specific place, but is near the northern border of the Tuileries District, which is again west from Place Vendôme. The first symbol can be found directly east in Place Vendôme at the base of the statue in the center of the plaza. You start this set of riddles on the building of the viewpoint for the Feydeau District in the northeast. To find the last symbol, go to the roof of the café and reach the dome at the very top of the building. When starting the riddle, use eagle vision to find the symbol right above the text, then go up the main stairway and look around the room for a painting with another symbol on it. The first riddle is obviously going to be the easiest one.