Should a French drain be located near the water source or the foundation?
It’s better to install your French drain at the point you are trying to drain. 

If you are protecting a basement, I’d install the drainpipe BELOW the concrete basement slab a minimum of 5-6”. 

Remember, water will go in the direction of least resistance. When it’s moving through the soil/rock and hits the drainpipe, it will flow in the pipe much faster than in the soil/rock, thus causing the water to flow towards the pipe. 

Water can move sideways through the soil or it can rise up through the soil from a rising watertable.