C12

C12 is building useful quantum computers by crafting the highest quality qubits using ultra-pure materials and perfected processes to control every individual electron. Launched in 2020 by twin brothers Matthieu and Pierre Desjardins, C12 is a spin-off of the Physics Laboratory at the École Normale Supérieure in Paris. We are pioneering a new approach to quantum computing—using carbon nanotubes to create ultra-pure qubits, enabling better control, reduced noise, and a scalable hardware platform. In June 2024, we raised €18 million in our second funding round, backed by Varsity, EIC Fund, Verve Ventures, and existing investors including 360 Capital, Bpifrance Digital Venture, and BNP Paribas Développement. This follows a $10M seed round in 2021. With this support, we aim to demonstrate high-fidelity entanglement between distant spin qubits—a key step toward building large-scale, fault-tolerant quantum processors. We have also inaugurated the Quantum Fab, our dedicated quantum production line in central Paris, and launched industrial collaborations across chemistry, optimization, and defense. Today, C12 operates from two offices on either side of the Panthéon, including a new space opened in 2025 to support our growing team. C12 currently employs over 50 people across 20 nationalities, including 22 PhDs, all working towards one mission: to lead the next materials leap in quantum computing. Silicon powered classical computing. It’s time for carbon to do the same for quantum.