Gradium, a Paris-based startup that offers voice AI models, reopened its seed round to new investors, including Nvidia, and has now raised $100 million in total for the round, it said Thursday.

The company is using the cash to open an office in the Bay Area and compete for talent there, “strengthening its position at the heart of the world’s leading AI ecosystem,” as Gradium put it. Paris is a major European hub for AI, so this is an interesting recognition of the benefits for AI startups of being close to Anthropic, Google, Meta and OpenAI.

Gradium originally launched by stealth in December with $70 million from an impressive roster of investors, including FirstMark Capital, Eurazeo, DST Global Partners, Eric Schmidt, and French telecom billionaire Xavier Niel.

The startup emerged from the French artificial intelligence lab Kyutai (a lab backed by Niel). Both Kyutai and Gradium were co-founded by Neil Zeghidour, a researcher who previously worked at Google Brain, DeepMind, and Facebook.

Gradium is working on audio models that deliver voice at scale with ultra-low latency—that is, AI voices that respond almost instantly, without that awkward pause that often creeps into AI agent conversations.

However, the company has plenty of competition, from other voice AI startups like ElevenLabs, valued at $11 billion in February, to major voice-savvy model makers like Google’s Gemini. But Gradium seems to be gaining traction anyway. Since launching in December, Gradium says it has landed some big customers, including French automaker Renault.