Hi Jonathan,
In France the limit in towns is as Simon has said 50 kph. There are no speed signs as such but it applies as soon as you get to the large oblong sign with the town name on it, this may go up to 70kph but there will be a speed sign above the town name to let you know this, it can also go down to 30 usually if there is a sharp blind bend, restricted width between buildings, speed hump to slow traffic down near a pedestrian zone or school.
On single carriageways and dual carriageways, what we know here in France as National and Departmental roads, the limit for goods vehicles is 80kph and motorways it’s 90kph, unless of course these two limits have been reduced.