To make infiltrating the area a little easier, once you arrive at the dock, follow the shoreline all the way to the south until you find a cliff that you can climb. Keep the cliff wall to your right and follow the passage along the raised ledges here, across the branch and a bridge which will collapse under you.
As soon as you are across the bridge, look down to your right to spot a red objective marker here. it is actually pointing to a barrel just out of sight behind the front of the building below. Fortunately, we have shrapnel grenades. Pull your launcher out and line up a shot with the barrel – but don’t fire right away, if you are patient, one of the French officers we need to kill will come and stand right next to it for us. When that happens – Bam! Two for the price of one!
The final two enemies that we need to kill are located in the village proper. So make your way down to the populated area. The captain is flanked by a pair of guards and will usually patrol from north to south and back again in front of the General store. The other officer patrols from east to west and back again, again by the icon for the general store. Fortunately, there are plenty of hiding spots and stalking zones around so you should have no trouble knocking those two trouble makers off.
Once all three objectives have been completed, the settlement take over will be complete.