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March 23, 2026

Inside the multi-million-dollar underground quantum lab in the heart of Paris

Quantum startup C12 has built a 1,000 square metre lab in the French capital’s historical centre, where it assembles quantum computers


C12 creates “spin qubits” from the spinning movement of electrons trapped on a conventional semiconductor device. Credit: Sophie Derrien

When Emily Cooper makes it to the top floor of her Parisian apartment block in the first episode of Emily in Paris, she dramatically opens the windows of her new home to the view of a charming square featuring a dreamy café-and-sun-soaked-terrace combo. Little did she know that tucked on the corner on the left-hand side of the street, an underground quantum lab was in the works.

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A picture of the square featuring the apartment block from Emily in Paris and the entrance to C12's office and lab
Entrance to C12's office and lab
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Human hands manipulating one of C12's quantum chips. Credit: Sophie Derrien
C12 creates “spin qubits” from the spinning movement of electrons trapped on a conventional semiconductor device. Credit: Sophie Derrien
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A C12 employee working in the startup's cleanroom, where it manufactures semiconductors. Credit: Sophie Derrien
The cleanroom is where C12 manufactures its own semiconductors. Credit: Sophie Derrien
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A C12 employee working in the room where carbon nanotubes are grown. In the background, the &quot;oven&quot; where carbon nanotubes are produced
C12 has developed its own chemical process to fabricate and manipulate single carbon nanotubes
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An assembled quantum computer in C12's data centre
At the ground floor level C12 keeps assembled quantum computers in a miniature version of a quantum “data centre”
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Daphné Leprince-Ringuet

Daphné Leprince-Ringuet is a senior reporter for Sifted, based in Paris. She covers French tech and writes Sifted's AI and Deeptech newsletter . You can find her on X and LinkedIn

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