If you install a letterbox you should take account of the following requirements:
- The letterbox must be placed within reach (free, easy and without danger) at the border of the public highway.
- The house number must be visible and legible from the location of the letterbox. If you also have a box number, please mention it clearly visibly and legibly on or near the letterbox concerned.
Standards for letterboxes:
- The letterbox aperture must be at least 23 cm wide and 3 cm high.
- The lower edge of the aperture must be situated at a minimum height of 70 cm and the upper edge of the aperture can be situated at a maximum height of 170 cm above the place from where one usually has access to the letterbox.
- The letterbox must be large enough to be delivered a C4 size unfolded item (229 mm by 324 mm) with a 24 mm thickness without damage.
For full details of the regulations, consult the official texts, available via the following link: Justel database.