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This month, let’s meet Guillaume MERCIER, professor of ethics and strategy, at the Lille campus since 2016.

Each year, more than 600 professor-researchers on IÉSEG’s Lille campus and Paris-La Défense campus contribute to the students’ learning journeys, enhancing their chances of achieving their professional goals and thriving in their careers. 

“Faculty in the Spotlight” is the monthly feature that offers a closer look at IÉSEG’s professors—their background, what they teach, why they joined IÉSEG, fun anecdotes and more.

Can you tell us about your background before joining IÉSEG?

I earned a Master’s in Management and another one in Political Sciences. After my studies, I had two very different organizational experiences: I spent three years as a monk, and then worked three years as a strategy consultant. Although these two experiences were almost opposite, both were extremely rich on a human level and deeply shaped my academic thinking.

I then pursued a PhD in “Management Sciences & Business Ethics,” focusing my dissertation on caring, and began teaching my first courses. I used my two prior experiences—monastic life and strategy consulting—as research fields. I observed how the practice of caring could differ profoundly in its foundations, depending on the organizational context.

These years helped me understand what truly motivates me: understanding and transmitting knowledge. In fact, I see a common thread in my two previous experiences—religious life, which seeks to understand and share spiritual and human truths, and consulting, where the goal is to help understand in order to guide decision-making. These two axes—understanding and transmission—are, in my view, at the core of my life as a professor.

Why did you choose IÉSEG?

I joined IÉSEG in 2016. At the time, I was looking for a position that would allow me to live in a way that aligned with my values. After speaking with a colleague who was already working there, and then with the professors I met during the recruitment process, I felt it was an environment that suited me—one in which I would feel at ease.

I was particularly drawn to this mix of ambition and humanity. IÉSEG is an ambitious school, but without excess; it fosters professional success and personal growth while leaving room for human values and personal life.

What are your teaching and research areas?

I teach strategy and ethics, both part of the same department: Management & Society. Ethics extends my existential and philosophical reflections. I have studied philosophy extensively—especially during my years in religious life—and it continues to nourish my thinking today and to shape my courses.

As for strategy, my consulting experience is my foundation. I enjoy teaching this subject because it places students in the position of decision-makers: for three hours, they become Steve Jobs or Jeff Bezos, asking themselves whether they should acquire a company, merge, or enter a new market. It’s very stimulating for them to immerse themselves in real-world situations!

In my research, I focus mainly on ethics—studying caring within organizations, among leaders, and in power relationships. I am also interested in cooperation between humans and artificial intelligence systems.

You teach ethics. How do you approach this topic with your students?

One of the courses I teach is the 3rd-year business ethics class of the Grande École Program. It’s a core, mandatory course, and I consider it essential. I don’t think many business schools in France offer mandatory ethics courses, and this was one of the reasons I chose to join IÉSEG.

In this course, I give students the opportunity to ask themselves real questions—questions that companies will never ask them—such as those related to integrity or the meaning of their professional life. Sixteen hours of class won’t change an entire life… but sometimes, a seed is planted: an example, a case study, a sentence that comes back later, at a difficult decision point.

I often tell them: “A successful professional life is not necessarily a successful life.”

The goal of the course is to help them think about the coherence between their values and their professional choices, to become professionals who are both ethical and true to themselves. It’s ambitious, for sure, but that is precisely the goal of this course: helping them succeed in their professional lives.

What about your strategy courses?

Today, I teach strategy in the Master in International Business, to a highly international postgraduate audience. It’s a fairly long course—about 40 hours. What I particularly appreciate is the quality and richness of the discussions.

Participants generally have prior professional experience, sometimes substantial: some have worked for several years, others have started their own business, and others come with a clearer understanding of what strategy looks like in real organizational contexts. This allows for deeper discussions in class. Students draw on their own experiences, concrete cases, their ambitions, and their strategic dilemmas. For them, these are not abstract theories—they are questions they encounter in their professional lives.

Strategy is another facet of the question of ethics: how can we make good decisions—fairly and responsibly?

What are your teaching methods?

I am very fond of role-playing and simulations. Ethics can feel abstract for young students, so placing them in the shoes of an employee or manager helps them confront concrete dilemmas, such as: How would I react if my boss asked me to lie to a client?

This allows them to “practice”—just as an actor rehearses before a performance—the situations they will very likely face at some point in their careers. When these situations arise in real life, they will already have thought them through, taken a step back, and may be better equipped to make the right decision.

There’s another exercise I enjoy using in ethics courses: a 40-minute simulation of an entire professional life, where students must make both major and minor decisions throughout a fictional career. At the end, we reflect together: which choices led to a coherent, balanced life, and which led them away from the path they intended to follow? It’s a playful yet profound way to address big questions: What kind of life do I want? What does a successful life mean to me?

I also occasionally invite corporate ethics professionals to class. Together, we design real cases—such as whether a company should remain in a country after a coup d’état. These concrete testimonies show students that ethics is an integral part of professional life—it is not a moral luxury, but a daily organizational concern.

I speak less directly about philosophers than I used to, but I bring them to life through discussions and case analyses.

What does IÉSEG’s Vision—“Empowering Changemakers for a Better Society”—mean to you?

It resonates deeply with me, because it aligns with my view of teaching. Training changemakers is not only about learning how to transform organizations—it’s also about learning how to transform oneself. My courses aim to foster this inner transformation: helping each student know themselves, understand what they want to contribute to the world, and find coherence between their values and their actions.

Changing society begins with changing the way one looks at life—and at one’s own life. And if my students have been able to take even a small step forward in this reflection during my courses, then that is already a great deal.