Règle correspondante
Netherlands
Practice Relating to Rule 37. Open Towns and Non-Defended Localities
Section B. Establishment of non-defended localities
The Military Manual (1993) of the Netherlands provides:
The authorities of a party to the conflict may declare as a non-defended locality any inhabited place near a zone where armed operations are launched. It is thus a unilateral declaration. Such a locality shall fulfil the following conditions:
(a) all combatants, as well as mobile weapons and mobile military equipment, must have been evacuated;
(b) no hostile use shall be made of fixed military installations or establishments;
(c) no acts of hostility shall be committed by the authorities or by the population; and
(d) no activities in support of military operations shall be undertaken.
The declaration shall be addressed to the adverse party and shall define the limits of the non-defended locality. The parties to the conflict may also decide by an agreement on the establishment of non-defended localities even if such localities do not fulfil the above-mentioned conditions.
A locality loses its status as a non-defended locality when it ceases to fulfil the conditions required or the conditions of the agreement concluded between the parties. 
Netherlands, Toepassing Humanitair Oorlogsrecht, Voorschift No. 27-412/1, Koninklijke Landmacht, Ministerie van Defensie, 1993, p. V-15, § 13.
The Military Manual (2005) of the Netherlands states:
0552. Parties to a conflict are prohibited from attacking undefended localities. This is a development of the older “open city” doctrine. The authorities of a party to a conflict may designate any inhabited place near the zone in which military operations are being conducted as an undefended locality. This, therefore, is a unilateral declaration.
During the Second World War, cities were several times declared “open”. In June 1940, for example, the French Government declared Paris and Bordeaux, among other places, open cities. In 1945 the Allies declared Rome an open city after landing in Italy.
0553. An undefended locality must meet the following conditions:
- all combatants, as well as mobile weapons and mobile military equipment must have been evacuated;
- no hostile use may be made of fixed military installations or establishments;
- no acts of hostility may be committed by the authorities or by the population;
- no activities in support of military operations may be undertaken. The declaration must be sent to the other side and must clearly state the boundaries of the locality.
In addition, the parties to a conflict may conclude agreements to create undefended localities, even if these do not meet all the conditions named above.
A locality loses undefended status if it no longer meets the set conditions or agreed terms. The presence in the locality of persons who enjoy special protection (e.g. civil defence personnel – see point 0556 below) and police units does not conflict with the conditions. 
Netherlands, Humanitair Oorlogsrecht: Handleiding, Voorschift No. 27-412, Koninklijke Landmacht, Militair Juridische Dienst, 2005, §§ 0552–0553.