Sebastian Flack is a Co-Founder of Sidestream and the person who leads our work across Germany and the wider DACH region. He is a systemic coach, supervisor and consultant, and he brings the half of behaviour change that a slide deck can never reach: the human system around the person. Where his Co-Founder, Ben Laumann, comes from organisational psychology and immersive theatre, Sebastian comes from the systemic tradition, the practice of reading people inside the relationships, teams and structures they actually sit in. Put the two together and you have the foundation of how we think about lasting change.
A Systemic Practitioner, Not A Lecturer At The Front
Sebastian works as a freelance consultant and systemic coach, guiding organisations, running seminars and teaching at universities. He studied social science at Ruhr University Bochum, and he has built a practice around systemic consulting, coaching and organisational development. The thread through all of it is a refusal to treat people as empty vessels to be filled. He does not stand at the front and transmit. He asks the question that lets a team see its own pattern, and then he gets out of the way while they work with it.
That stance matters because it is the same one Sidestream takes into every room. We do not believe people change because someone told them to. They change because something shifts in how they understand themselves and the people around them. Systemic practice gives that shift a method. It turns a vague sense that a team is stuck into a clear picture of who responds to whom, where the trust breaks, and which small move would unlock the rest.
Why Systemic Practice And Immersive Change Belong Together
Some things cannot be taught, they have to be felt. Systemic work has always known this. You can explain a team's dynamic to it for an hour and watch nothing move, then put the same people through one honest, structured conversation and watch them recognise themselves in seconds. That recognition is the whole point, and it is exactly what Sidestream's immersive method is built to manufacture on purpose.
Sebastian's systemic lens and our immersive practice meet at the same conviction. Real behaviour change happens through lived experience that makes the memory stick. A simulation puts a person back into the difficult version of their job, watched and coached, so the new behaviour is rehearsed rather than merely described. Systemic coaching does the reflective half: it helps the person and the team make sense of what just happened, name the pattern, and carry the change back into the structure they came from. The experience creates the moment. The systemic conversation makes it hold.
This is also why we measure what people do rather than what they thought of the day. A satisfied delegate proves very little. A manager handling the hard conversation differently a month later, inside the same team and the same hierarchy, proves everything. Systemic practice keeps our attention on that level, on the behaviour as it lives in the real system, which is where our case studies are written and where any honest claim about change has to be settled.
What Sebastian Leads At Sidestream
From Germany, Sebastian anchors our presence across the DACH market and brings the systemic dimension to the way we design and deliver. For German and Austrian and Swiss organisations he is the first point of contact and the person who makes sure an immersive programme is built around the specific people, culture and structure in front of us, not a template. He works alongside Ben so that the science of behaviour, the craft of immersive experience and the discipline of systemic reflection arrive in the same engagement rather than as three separate things.
It is the combination that defines Sidestream. Evidence-based design, a felt experience that lands under the skin, and a systemic practitioner who makes sure the change survives contact with the real organisation. If that is the kind of work your teams need, see how we work with companies or read about our approach first.