Lehmann's design work has been the subject of four solo and dozens of group exhibitions worldwide.
Solo exhibitions have been held at the Bauhaus in Dessau (1997), AEDES Gallery in Berlin (1996), Plan '99 in Cologne (1999), and QUT in Brisbane (2003). His work was also featured in the 3rd International Architecture Biennale in São Paulo (1997), and the group exhibition Abundant in the Australian Pavilion at the Venice Architecture Biennale (2008).
Work produced in his studios has been published and exhibited internationally.
Curatorial Projects and Artist Collaborations
For over 30 years, Lehmann has championed interdisciplinary collaboration between architects and artists. As creative director and curator, he has conceived and delivered large-scale international events in which artists and architects collaborate to create site-specific, full-scale installations in urban public spaces — spanning five cities across four countries:
Exhibitions and Curatorial Projects
Rethinking: Space–Time–Architecture, Berlin, 2000 — presented as part of the International Union of Architects (UIA) World Congress. The project resulted in over 100 site-specific collaborative installations in the public spaces of Berlin.
Absolutely Public, Brisbane, 2005 — commissioned by Brisbane City Council and Southbank Corporation
Back to the City, Newcastle, 2008 — commissioned by the Newcastle Alliance and ArtsNSW
Hidden Networks: Laneways/City Spaces, Sydney, 2009 — commissioned by the City of Sydney
Hub-to-Hub, Singapore, 2010 — commissioned by the Urban Redevelopment Authority (URA), Singapore
A catalogue was published for each of these events. The temporary installation projects are documented in 'Back to the City: Strategies for Informal Urban Interventions' (Hatje Cantz, Stuttgart and Berlin, 2009).
In 1994, Lehmann curated the exhibition ‘Arata Isozaki: Towards the Third Generation Art Museum’, which was exhibited at AEDES Gallery in Berlin and Vienna (catalogue published).
In 2010, his collaborative project proposal ‘Women’s Suffrage Memorial, Brisbane’ with artist Cida de Aragon was selected for realization in public space at Brisbane City Hall.
In 2019-2021, he was appointed as a member of the International Advisory Board for the Italian Pavilion ‘Resilient Communities’ at the 17th Venice Architecture Biennale, Italy.
In 2026, Lehmann served as content advisor for Science of Sustainability, an exhibition installation at the Springs Preserve Museum, Las Vegas.
I BELIEVE IN THE POWER OF SMALL GOVERNMENT, INNOVATION, ENTREPRENEURSHIP, AND THE COMPETITION OF IDEAS.
Optimism and Common Sense Thinking
Lehmann has been associated with Libertarian thinking, putting a strong emphasis on freedom of speech, property rights, deregulation, small government, as well as free markets.
He believes that strategies for resource-efficient cities must be grounded in scientific evidence and rigorous research — not ideology, dogma, or political convenience. On environmental policy, he advocates for practical, evidence-based measures that genuinely protect the environment and biodiversity, rather than performative gestures that satisfy lobbies while delivering little real impact.
With faith in our capacity to deliver a positive future, Lehmann has built businesses and worked under multiple governments across different countries. The pattern is consistent: where things work, the government does a handful of things exceptionally well and otherwise stays out of productive people's lives.
He makes the case for leaner, smarter governance. Bloated state and federal bureaucracies cost taxpayers billions annually — and the damage goes beyond dollars. He thinks that excessive, poorly written regulations stifle productivity, suppress innovation, and entrench the very inefficiencies they claim to address. More rules rarely mean better outcomes.
