Articles 678 and 679 of the Civil Code indicate the distances to comply with. These measurements vary according to the position of the opening
If the view is direct (you can see into your neighbour’s home without even leaning over), the wall in which the window is going to be placed must be at least 1.90 m from the property line. If you extend this opening with a balcony or a terrace, the distance will be measured from the far end of this construction.
If the view is oblique, you need to comply with a minimum distance of 0.60 m from the left or right angle of the window.
Note: if you do not comply with these rules, your neighbour can force you to remove the window. Pay careful attention. In any case, inform your neighbour of the work you are planning ahead of time in order to maintain a good relationship.