Human Resources Director

Who we areWe are Mantle 8, a clean-tech start-up revolutionizing natural hydrogen exploration with cutting-edge technology and geologic strategies. Backed by leading clean-tech investors including Breakthrough Energy Ventures and Kiko Ventures, we're scaling up affordable natural hydrogen exploration — and you could be a key part of this journeyNatural hydrogen offers an affordable, abundant energy source with significant potential in Europe. At Mantle 8, we leverage 20+ years of expertise in geology, predictive modelling, and 4D imaging to pinpoint optimal reserves.What the role is aboutAs Human Resources Director, you will build and lead Mantle8's full HR function during a pivotal scaling phase. You will act as a strategic partner to the executive team, shaping our people strategy, culture, and organizational development across France and future international hubs.This is both a strategic and hands-on role: you'll design HR policies, oversee talent acquisition, implement performance frameworks, drive leadership development, and ensure Mantle8 remains an exceptional place to work.You will lay the foundations of a robust HR organization while supporting a fast-moving deep-tech start-up environment.What you'll be doingPeople Strategy & Leadership:Build and lead Mantle8's HR function from the ground up, aligned with company growth objectivesAct as a strategic advisor to the CEO and executive team on people, culture, and organizational designDevelop HR policies, processes, and frameworks ensuring consistency and scalabilityTalent Acquisition & Employer Branding:Lead recruitment strategy for technical, scientific, and corporate rolesBuild a strong employer brand to attract top global clean-tech talentImplement hiring processes and onboarding programsEmployee Development & Performance:Design and implement performance management, career developmentDevelop leadership and training programs to support managers and high-potential employeesFoster a culture of continuous feedback, learning, and excellenceCompensation, Benefits & Compliance:Oversee compensation and benefits programs ensuring competitiveness, cost efficiency, and fairnessEnsure full compliance with French labor laws (Code du Travail) and future international jurisdictionsEstablish HR metrics, reporting, and data-driven decision-makingCulture, Engagement & Change Management:Champion Mantle8's culture, values, and mission as we scaleLead employee engagement initiatives and internal communication programsSupport organizational transformation in a fast-growth environmentWhat we're looking forEssential Requirements:5+ years of experience in Human Resources, including HR leadership rolesProven track record in scaling HR functions within fast-growing companies (start-up, scale-up, or innovation-driven environments)Strong knowledge of French labor law, employment frameworks, and HR best practicesExperience with talent acquisition, performance management, compensation frameworks, and organizational developmentFluency in English and FrenchLocated in Grenoble or willing to Relocate (100% on-site required)Highly Valued:Experience in deep-tech, energy, industrial, or scientific organizationsFamiliarity with Lucca (our main SIRH platform)Prior experience in international HR operations or expansion incl. visa processes for internationalsPersonal Qualities:Strategic thinker with strong operational executionEmpathetic and trusted people partner with high emotional intelligenceExcellent judgment, discretion, and confidentialityAbility to thrive in a fast-paced start-up environmentPassionate about clean-tech and building impactful teamsWhat we offerCompetitive Package:Attractive salary with meal, vacation, and CESU vouchersCorporate welfare plan and supplementary health insuranceIndefinite contract (CDI – Cadre) with full French employment protectionsUnique Opportunity:Shape Mantle8's HR strategy from day oneDirect involvement in scaling a pioneering clean-tech companyClose collaboration with founders and scientistsEmpowered leadership role with high visibility and impactCareer Development:Opportunity to build and lead a full HR organizationLong-term progression as the company expands internationallyReady to help revolutionize clean energy? Join us in building the future of natural hydrogen explorationMantle8 is an equal opportunity employer committed to diversity and inclusion. We welcome applications from individuals of all backgrounds.