Junior Payroll Specialist H/F

ABOUT ALTA ARES Alta Ares is an air defense Neoprime. We build AI-guided interceptors to counter drones and cruise missiles, along with the software platform that powers them. Our customers are NATO-aligned militaries and defense institutions, and our systems are regularly deployed during live exercises and operational demonstrations across Europe, the Middle East, and Asia. Founded in 2024, we have grown to 90 people, raised over $60M, and increased revenue 40× this year. We are now entering a new phase of international expansion, industrial scaling, fundraising, and product development. ROLE & MISSION As Junior Payroll Specialist, you will own the operational execution of Alta Ares' French payroll and support the People team on all compensation and administrative matters. You will be the go-to person for payroll accuracy, social declarations, and employee administration in a fast-scaling startup where getting it right, every month, matters. You will work directly with the People & Talent Lead and Finance team, operating PayFit as the backbone of the payroll function and contributing to the continuous improvement of HR-admin processes as Alta Ares grows from ~52 to 100+ employees. This is a hands-on, ownership role not a back-office support position. You will manage the monthly payroll cycle end-to-end, handle employee queries directly, and be a trusted, reliable presence in the People team. Payroll Operations - Own the monthly payroll cycle end-to-end on PayFit: variable element input, payslip validation, anomaly detection, and final approval coordination - Collect, verify, and integrate all monthly variables: absences, RTT, overtime, bonuses, expenses, and BSPCE-related elements - Ensure accuracy and compliance of all payslips with applicable collective agreement (Syntec) and French labour law - Manage payroll for all employment contract types: CDI, CDD, apprenticeship, and VIE (in coordination with Business France) - Handle employee entries and exits from a payroll perspective: onboarding setup, offboarding calculations (solde de tout compte, indemnités) - Coordinate with the external social security bodies: URSSAF, CPAM, prévoyance, mutuelle, and retraite complementaire Social Declarations & Compliance - Prepare and submit monthly and annual social declarations: DSN, URSSAF, and applicable reporting obligations - Monitor regulatory changes in French payroll law and collective agreement updates (Syntec) and implement necessary adjustments in PayFit - Track and manage sick leave, maternity/paternity leave, and other statutory absences in coordination with CPAM and prévoyance - Ensure compliance with legal minimums: SMIC, mandatory benefits, and Syntec classification benchmarks - Maintain organised payroll archives and documentation audit-ready at all times Employee Administration & HR Ops - Serve as the first point of contact for employee payroll queries: responding accurately, promptly, and with the right level of explanation - Manage administrative employee lifecycle documents: contrats de travail, avenants, attestations, and certificats de travail - Maintain and update employee records in PayFit and internal HR tools (Notion) - Support the onboarding process from an administrative standpoint: DPAE, mutuelle affiliation, and prévoyance enrollment - Contribute to the offboarding process: solde de tout compte, documents de fin de contrat, and Pôle Emploi attestations Finance & Reporting Coordination - Produce monthly payroll reports and cost breakdowns for the Finance team - Support the preparation of payroll-related provisions and accruals for accounting purposes - Contribute to the annual salary review process: modelling compensation changes and their payroll impact - Assist in the preparation of payroll data for audits, fundraising due diligence, and investor reporting CANDIDATE PROFILE - 1–3 years of experience in payroll administration, HR operations, or a combined payroll/HR-admin role - PayFit experience is mandatory: you must be operationally proficient in PayFit from day one - Startup experience is mandatory: you are comfortable in a lean, fast-moving environment where processes are still being built and autonomy is the norm - Solid understanding of French payroll mechanics and social legislation - Familiarity with Syntec collective agreement is a strong plus - Experience managing a full monthly payroll cycle independently is valued Skills & Qualities - Rigorous and meticulous payroll errors have real consequences for employees, and you take that seriously - Organised and reliable: you meet monthly deadlines without fail, even when the environment around you is moving fast - Proactive: you flag anomalies, anticipate bottlenecks, and propose improvements without waiting to be asked - Service-minded: you handle employee payroll queries with patience, accuracy, and discretion - Comfortable with numbers: payroll is data-heavy and you are at ease with spreadsheets, reconciliation, and cross-checking - Discreet and trustworthy: you handle sensitive compensation and personal data daily - Fluent in French is mandatory; English proficiency is a plus for international entity coordination