Related Rule
France
Practice Relating to Rule 73. Biological Weapons
France’s LOAC Summary Note (1992) states that it is prohibited to use biological weapons. 
France, Fiche de Synthèse sur les Règles Applicables dans les Conflits Armés, Note No. 432/DEF/EMA/OL.2/NP, Général de Corps d’Armée Voinot (pour l’Amiral Lanxade, Chef d’Etat-major des Armées), 1992, § 4.6.
France’s LOAC Teaching Note (2000) includes biological and bacteriological weapons in the list of weapons that “are totally prohibited by the law of armed conflict” because of their inhuman and indiscriminate character. 
France, Fiche didactique relative au droit des conflits armés, Directive of the Ministry of Defence, 4 January 2000, annexed to the Directive No. 147 of the Ministry of Defence of 4 January 2000, p. 6.
France’s LOAC Manual (2001) incorporates the content of Article 1 of the 1972 Biological Weapons Convention and makes reference to the 1925 Geneva Gas Protocol. 
France, Manuel de droit des conflits armés, Ministère de la Défense, Direction des Affaires Juridiques, Sous-Direction du droit international humanitaire et du droit européen, Bureau du droit des conflits armés, 2001, p. 22.
The manual further includes biological and bacteriological weapons in the list of weapons that “are totally prohibited by the law of armed conflict” because of their inhuman and indiscriminate character. 
France, Manuel de droit des conflits armés, Ministère de la Défense, Direction des Affaires Juridiques, Sous-Direction du droit international humanitaire et du droit européen, Bureau du droit des conflits armés, 2001, p. 54.
France’s Law on the Prohibition of Biological Weapons (1972) prohibits the production, retention, acquisition, stockpiling and transfer of biological weapons. 
France, Law on the Prohibition of Biological Weapons, 1972, Article 1.
France’s Code of Defence (2004) states:
The development, production, possession, stockpiling, acquisition, and transfer of microbiological agents, other biological agents and biological toxins, whatever their origin and mode of production, which are of a kind and quantity not suited for prophylactic, protection or other pacific purposes, are prohibited. 
France, Code of Defence, 2004, Article L. 2341-1; see also Article L. 2341-2.
At the Conference for the Supervision of the International Trade in Arms and Ammunition and in Implements of War in 1925, France, with regard to a Polish proposal to extend the prohibition contained in what became the 1925 Geneva Gas Protocol to bacteriological warfare, begged “to second the Polish proposal”. 
France, Statement of 8 June 1925 at the Conference for the Supervision of the International Trade in Arms and Ammunition and in Implements of War, Geneva, 4 May-17 June 1925, League of Nations, Records of the Conference, Doc. A.13.1925.IX, September 1925, p. 341.
At the Second Review Conference of States Parties to the Biological Weapons Convention in 1986, France stated that it
had not initially signed the [1972 Biological Weapons Convention] taking a critical view of the lack of provisions relating to verification, it nevertheless recognised the importance of its purpose. It therefore adopted at the national level provisions similar to those of the Convention with regard to the prohibition of the development, production and stockpiling of bacteriological (biological) and toxin weapons and their destruction. Thus, since that date France has for its part assumed the obligations in this field stemming from the Convention of 10 April 1972.
Accordingly, it added, all technological research and work on biological weapons have been interrupted. The biological agents and toxins produced have been destroyed. Since then no research has been undertaken on the production for hostile purposes of biological or toxin weapons or on the dissemination of such agents. No aid has been given to third countries in these fields. Therefore, France has fulfilled all the obligations stemming from Articles I, II, III, and IV since 1972, in other words, well before its accession to the Convention (27 September 1984). 
France, Statement at the Second Review Conference of States Parties to the Biological Weapons Convention, Geneva, 8–26 September 1986, UN Doc. BWC/CONF.II/3Add. 5, 25 August 1986, pp. 1–2.
In 1991, during a debate in the UN Security Council preceding the adoption of Resolution 699 concerning the destruction of biological weapons in Iraq, France held that the ban on Iraqi possession of biological weapons was carried out with the perspective of regional and global disarmament. 
France, Statement before the UN Security Council, UN Doc. S/PV.2981, 3 April 1991, p. 92.
A French Government publication issued in 2005 and entitled “Fighting Proliferation, Promoting Arms Control and Disarmament: France’s Contribution” states:
Biological weapons
A biological weapon is a system capable of disseminating pathogens (biological or toxic agents). These may be natural, or genetically modified to enhance their characteristics.
Developments in biotechnology could be used for the production or the improvement of biological weapons and provide access to new biological agents better suited to military uses. In such cases, the development of vaccines and treatments could prove to be more complex.
France’s approach
Faced with the threat posed by biological weapons, France’s approach is based on a recognition of the unique nature of these weapons, and notably the potentially dual nature of research activities in biology.
France’s primary aim is to combat biological proliferation and weapons. To that end, adherence to export control measures, together with stronger international control measures, are of crucial importance. France played an active role in negotiating, in 1995, a protocol strengthening the 1972 Biological and Toxin Weapons Convention and is working in concert with its EU partners to achieve its universalization.
It is also necessary to be able to respond to the consequences of a biological attack. In order to protect its civilian population and armed forces against the effects of biological weapons, France is developing measures for protection, prophylaxis and treatment, early-warning and detection procedures, and means for decontamination. The BIOTOX plan is one element of this approach.
Actions undertaken
France has consistently sought to strengthen measures to combat the biological threat. France is the depositary of the 1925 Geneva Protocol. In 1996, France lifted its reserv[ations] on the possible use of such weapons in reprisal which, like most signatories, it had appended to the Protocol upon ratifying. The aim of this decision was to strengthen the obligation to ban all use of such weapons.
In 1984, France became party to the 1972 Bacteriological (Biological) and Toxin Weapon Convention (BTWC). It had previously considered the text weakened by the absence of verification provisions and, as early as 1972, had adopted national legislation on biological weapons incorporating provisions similar to the obligations laid down by the BTWC. Since ratifying the Convention, France has worked ceaselessly towards strengthening it and improving its implementation.
Following the failure in 2001 of negotiations on a protocol to strengthen the 1972 Convention, one important aim of which was to establish an inspection regime, France, along with its EU partners, expressed its commitment to the adoption of an alternative monitoring mechanism: an annual conference combined with a meeting of experts charged with studying implementation measures. These annual meetings have the task of examining specific measures: including, in 2003, national legislation and the securing of pathogens; in 2004, international control in the event of alleged use of biological weapons and surveillance of epidemics; and in 2005, a code of conduct for scientists.
The results achieved so far underscore the wisdom of this approach aimed at working towards the strengthening of the 1972 Convention. For example, examination of national legislation and of the control of pathogens is a prerequisite for any further consideration of the ways in which the authority of the BTWC can be consolidated.
Other means of control
As in the case of chemical non-proliferation, states have adopted a series of national export control measures in the biological sphere, coordinated through the Australia Group. 
France, Government, Fighting Proliferation, Promoting Arms Control and Disarmament: France’s Contribution, 2005, pp. 34–40.
In a white paper on “Defence and National Security” published in 2008, France’s Ministry of Defence stated:
The fight against the proliferation of weapons of mass destruction and their means of delivery will indeed continue to be a priority …
In order to be efficient, the fight against proliferation must be based on … the universalization and full implementation of the international conventions signed by the vast majority of States (… [including the] Biological Weapons Convention, or BWC …).
The Proliferation Security Initiative or PSI … initially comprised 11 States. It now includes almost 90 signatories. It aims at improving operational cooperation among governmental actors in order to identify and prohibit the transfer of materials or equipment that may contribute to programmes on … biological … weapons and their means of delivery.
In December 2003, the European Union adopted … an action plan against the proliferation of CBRN weapons [chemical, biological, radiological and nuclear weapons], which covers all aspects of the fight against proliferation. In particular, the EU made the implementation of its commercial or cooperation agreements with third countries conditional on the latter’s respect for their international commitments regarding non-proliferation.
Biological weapons are [a] point of concern. All Western countries have renounced their programmes in this domain, and have continued only with the activities [needed] for protection against potential attacks.
The BWC was adopted in 1972. It has been signed by 161 States but so far does not provide for any verification system.
[France] will contribute to the aid proposed to States by the European Union in order for them to sign and apply the [BWC] … In general, [France] will develop its military and technical expertise that can eventually serve in the detection and repression of the trafficking in material and equipment for the conception and production of these weapons [biological weapons].
Basic and applied research in these fields will be funded, as well as work conducted by French scientific laboratories. An effort regarding the training in clandestine programmes will be undertaken for the customs officers who are in charge of controlling war-related material as well as objects of both civilian and military use.
[Carrying out] missions for the fight against proliferation and the control over disarmament agreements will be among the objectives of both the armed forces and civil security, taking into account the predictable increase in control activities. Priority will be given to means of safely destroying illegal biological … installations, as well as to means of defence and protection, in particular the biological ones.
[France] will be particularly active in the fight against the proliferation of … biological … weapons, as well as of missiles that could deliver them. 
France, Ministry of Defence, Defence and National Security: The White Paper, 17 June 2008, pp. 117–119, 161–162 and 315.
[emphasis in original]