Murder of a far-right activist by antifas in Lyon: what mechanisms lead to political violence?

The death of Quentin Deranque in Lyon (France) and the arrest of antifascist activists have reignited a heated debate over political responsibility, but also over the mechanisms that lead individuals to commit acts of violence. In this analysis, Antoine Marie (CEVIPOF/ Sciences Po) argues that political violence is rarely the product of individual madness; rather, it typically unfolds through a gradual process: informational isolation, conspiratorial worldviews, and the dehumanization of opponents—culminating in group dynamics that ultimately trigger the shift to violent action.

[This article is an adapted translation from a piece that first came out in our partner The Conversation, France, in French, on Feb. 18th 2026]

The death on February 14 of Quentin Deranque, 23, a far-right activist beaten to death in the streets of Lyon two days earlier, led to the arrest of 11 “antifa” activists, including a parliamentary aide to La France insoumise (LFI). This event, which has sparked heated debates in France about LFI’s political responsibility, also raises questions about the individual and collective processes that can lead to radicalization and political violence.

How do seemingly ordinary people come to commit politically motivated group violence? Psychologist Fathali Moghaddam proposed a now-classic model, “the staircase to terrorism”, which applies quite well to political violence in general. According to his analysis, violent political action is the final step of a long staircase that rises and narrows very gradually.

First step: selective exposure. One comes to consult only political information sources that reinforce one’s negative perceptions and partisan analyses of complex political issues. One gradually ceases contact with nuanced, intellectually competent interlocutors capable of defending the opposing viewpoint.

Second step: the acquisition of highly selective views of political and societal issues, sometimes with conspiratorial overtones. On the far right, for example, the fear of “great replacement” of White majorities by non-White ethnic minorities considerably exaggerates the scale of demographic changes taking place in the West and their cultural consequences. On the far left, one finds discourses that, while not necessarily conspiratorial (although see this study on far left conspiracism), reveal an excessively negative representation of capitalism, focused on its contributions to inequality and undervaluing its contribution to the development of individual freedoms or the wealth of nations.

Third step: the dehumanization of the opposing camp. Notably through what Waytz, Young, and Ginges call “motive attribution asymmetry”: each side is convinced it acts out of love for its group and its causes, but attributes to the other side a motivation of pure hatred. This bias, observed by the authors among Israeli, Palestinian, and American (Republican and Democrat) populations, makes compromise much more difficult. In fact, Moore-Berg and colleagues have shown through experimental studies that these perceptions of hostility are massively exaggerated: Democrats and Republicans, for instance, overestimate the degree to which the other side hates them, and underestimate the authenticity of the outgroup’s moral motivations — misperceptions that in turn perpetuate reciprocal hostility.

Importantly, each step on the radicalization staircase is climbed in a way that is subjectively imperceptible. One does not wake up radical one morning: indoctrination is gradual. Moreover, ethnographic studies suggest that activists typically remain convinced, at every stage, that morality and truth are on their side.

Radicalization is thus most often not the reflection of a psychiatric pathology. It is rather an extreme version of ordinary moral and cognitive traits: outrage in the face of injustice, “us” versus “them” tribal thinking, solidarity and identity fusion with one’s group, hypersensitivity to social threat, the desire to protect a way of life that is dear to us, the delegitimization of those who disagree with us politically, etc.

Let us also emphasize the importance of the social motivations satisfied by the group: the radical group offers a sense of belonging, identity pride, and feelings of usefulness and meaningfulness.

And on the day of the violent riot itself, group dynamics do the rest. There is a status benefit among radical activists in showing that one is ready to act, and receiving punches activates fundamental instincts of self-defense through violence.

The far right commits more violence than the far left in contemporary France

Research shows that many mechanisms are common to violent radicalism on both the left and the right, even though the content of beliefs differs considerably.

It is also important to recall a significant asymmetry. The database compiled by Sommier, Crettiez, and Audigier (2021) records approximately 6,000 episodes of political violence over the period 1986–2021 and establishes that among the deaths from ideological violence, nine out of ten are victims of the far right. Far-right violence also tends to be directed against people, while far-left violence tends to be directed against property.

These figures remind us that political violence kills on both sides, but not in the same proportions.

Deradicalization: contact as an antidote?

How can the most extreme activists be deradicalized? One difficulty is that each camp refuses to concede that members of its own camp may have gone too far (as doing so appears as a “betrayal”). Each side is convinced that its own violence is merely a legitimate reaction to the other’s, as opposed to a decision that causally perpetuates the cycle of mutual hatred and violence.

Another barrier lies in the difficulty of reaching radical activists: they generally do not see their worldview and their commitment as antisocial, antidemocratic, or based on excessive certainties.

Yet research offers some leads, which have generally been tested on ordinary, non-violent partisans. The meta-analysis by Pettigrew and Tropp (2006), covering more than 500 studies, shows that intergroup contact — spending time face-to-face with an outgroup member, engaging in shared activities — robustly reduces hateful prejudice. Landry and colleagues (2021) showed that simply informing people that the other side does not hate them as much as they believe through short messages reduces dehumanization.

The key notions are encounter with individualized members from the other side, and reconnection with reality, to correct distorted perceptions of what the “enemies” actually think, rehumanize them, and reduce animus.

But the most radicalized individuals are typically very difficult to reach: they have very low trust in public institutions, in researchers, and their dehumanization of “enemies” is complete. They are often convinced that interventions “won’t work on them”, or show resistance to any questioning of their worldview.

Upstream, at a societal level, it is important to refuse any glorification of political violence in order to reduce the status incentives to commit it — just as it is recommended to limit the publicizing of terrorist attack perpetrators to diminish the prestige effect.

Downstream, de-escalation techniques must be systematically taught, such as refusing to respond to provocations (even verbal) with violence. The history of the American civil rights movement shows that nonviolence is not only morally superior but also strategically more effective — because it gives social movements greater “moral credit” among those who are not already their supporters (see the work of Chenoweth et al. on the long-term benefits of nonviolence).

Ultimately, since radicalization mechanisms are least rare among young people (especially men), they could be taught as early as middle school and high school, as is beginning to be done with disinformation in France in the current geopolitical context.

This article was written in collaboration with Peter Barrett (@Debatology), an expert on political polarization, lecturer at ESSEC and at the University of Cergy, France. Antoine owes Peter a lot when it comes to his understanding of the dynamics of polarization and depolarization.