Chief of Staff

Location: Paris or Montpellier (with international reach: USA / UK)

Report: CEO

Why is Celest.science recruiting a Chief of Staff?

At the crossroads of scientific excellence and the demands of global finance and insurance, Celest.science is looking for a Chief of Staff to turn a technological breakthrough into the industry standard for climate resilience.

In this critical phase of scaling toward our first million in revenue, you will serve as the CEO’s right hand, synchronizing go-to-market execution with our tech team. Your role is to structure internal growth and streamline operations to convert our climate models into "must-have" decision-making tools for the real economy.

By joining Celest now, you become the architect of our scale-up, ensuring that every scientific milestone translates into tangible impact for our clients.

Celest.science at a glance

Celest.science was born from the synergy between the world-class academic expertise of Pierre Gentine (CSO, Professor at Columbia) and the entrepreneurial vision of Léo Lemordant (CEO, repeat founder and expert in energy, finance, and climate). Our mission: to translate academic breakthroughs in climate science into operational tools for economic decision-makers.

Driven by a team of AI and climate engineers, our proprietary models offer the reliability and explainability currently missing in the market. By eliminating the "black-box" effect of climate forecasting, we are removing the primary barrier to its integration into corporate strategic decision-making.

We target sectors where climate uncertainty hits the hardest: insurance, reinsurance, and market finance. Already partnered with global leaders, Celest.science is becoming the go-to technological layer for securing tomorrow's assets.

Your Missions

Your role is built on three fundamental pillars, with a primary focus on business development.

1. Pre- and post-sales project management

Structuring & sales ops: Own the HubSpot CRM architecture (pipelines, automation, reporting) and drive the reactivation and follow-up of our existing lead portfolio.

Sales enablement: Develop sales playbooks and optimize marketing assets (decks, website, newsletters, white papers, use-case sheets, webinars, PR).

Lead generation: Execute targeted cold outreach and represent the company at key industry events and trade shows.

Strategic account management: Lead the operational follow-up for pilots and onboarding of our early customers.

Technical bridge: Manage projects by acting as the link between specific client needs and the engineering team.

Operational excellence: Define and track OKRs to ensure we hit the €1M ARR milestone.

Process optimization: Design internal workflows that scale without sacrificing agility or speed.

Strategic projects: Including tech partnerships, ecosystem mapping, and competitive intelligence.

Fundraising: Prepare materials and documentation for future funding rounds.

Market exploration: Validate product-market fit and identify new growth levers by testing prospect/product segments and synthesizing market feedback to guide product development.

Discovery: Lead discovery and qualification calls for complex sales cycles.

3. Operations

Funding and grants: Prepare financial communication and grant applications to secure non-dilutive funding.

Talent acquisition: Support the CEO in identifying and onboarding top-tier talent.

Culture: Actively build an optimal work environment and organize team highlights (offsites, seminars) to strengthen the bond between Paris and Montpellier.

CEO support: Coordinate between external providers (HR, accounting, finance) and the internal team.

Your Profile

A "swiss-army knife" with at least 2 years of experience, combining a scientific mindset with business acumen. You possess solid project management skills and are highly comfortable in client-facing roles. You are fully fluent in French and English.

• Scientific and AI literacy: You understand the stakes of Machine Learning and have a genuine interest in climate science.
• Analytical rigor: Proven ability to synthesize complex information into high-level commercial or marketing documents.
• Project management: Experience managing complex projects with multiple stakeholders (C-suite, engineers, researchers).
• Proactivity: You know how to prioritize your own workload in a fast-paced environment without needing daily hand-holding.
• Communication: You can bridge the gap between very different profiles internally and with external partners.
• Entrepreneurial grit: High resilience in the face of uncertainty and the ability to make decisions in ambiguous situations.
• Background: Graduate of a top-tier business or engineering school, with demanding initial experience in consulting or finance.

Why Join Us?

• Real-world impact: Tackle the defining challenge of our time: climate resilience.
• Unique credibility: Work alongside Pierre Gentine, a global authority in climate AI, and a world-class technical team.
• Maximum exposure: Get a front-row seat to the building of a French deep-tech startup.
• Culture of autonomy: We value trust and intellectual curiosity over rigid hierarchy. This freedom requires radical self-discipline: you are the guarantor of your own work quality and commitments.