French law has been built on the stark opposition between private interest (defended solely by its holder) and public interest (defended solely by the State). Situated between these two poles, the term "collective interest" is ambiguous and open to multiple interpretations. In the context of legal action, three meanings are relevant:
Collective interest is sometimes used to refer to the mere sum of individual interests. This is the case when an association is presumed to act "in the collective interest of its members" (case law of "defence leagues").
Collective interest can also refer to an interest that transcends private interests, aiming at the interest of an abstract category of people, like a profession. For instance, in union matters, the collective interest of the profession is at stake whenever there is a "disruption likely to be felt by each member of the union and harmful to the entire profession."
Lastly, collective interest can be understood as a "great cause" (e.g., combating racism, gender equality, environmental protection, etc.). In this case, collective interest appears to be a particular aspect of the general interest.
The boundaries between these understandings are porous. Advocates of a "great cause" consider it as an aspect of the general interest, while opponents typically view it as a mere category-specific interest.
Civil and criminal procedures were conceived in the 19th century based on the opposition between personal and general interest and for the defence of monetary interests. The defence of disinterested collective interests had to adapt to a system not built for this purpose.
In civil matters, pursuing legal action requires both an interest to act and the capacity to act. Generally, anyone defending their direct and personal interest automatically has the capacity to act. The same applies in criminal matters.
However, the law may establish specific rules for the capacity to act, particularly in cases involving collective interests. The defence of the collective interest can only be understood as defending the interest of others, hence requiring legislative authorisation.
As Louis Boré expresses, the defence of collective interest by an association historically rests on a "transcendent" legitimacy, i.e., derived from the State. Currently, only unions have general authorisation. Associations benefit from sector-specific authorisations limited to certain actions.
The issue has been posed differently in administrative matters. The Council of State has very early admitted the interest to act for associations for collective interests provided there is a direct link between the effects of the attacked decision, the social purpose of the association, and the territory where the group exercises its activities.
Recent case law has challenged the traditional model. Even without legislative authorisation, an association can take legal action in the name of collective interests provided these interests are in line with its social purpose. This new way of understanding the personal interest to act requires explanation, as it appears contrary to the texts.
The hypothesis is that jurisprudence considers the group, by aiming at the collective interest in its social purpose, to have "made its own" the collective interest pursued. Hence, the legitimacy to defend a collective interest is no longer "transcendent" but "immanent," meaning it arises from the will of the group's members.
