Conception / Mechanical Engineer (Internship or CDD)

Conception / Mechanical Engineer (Internship or CDD)

Location: Paris; candidates must already be based in Paris or be able to relocate immediately

Start date: ASAP

Contract: Internship or CDD, depending on profile and experience

Compensation:

• CDD: Approximately €1,500 net take-home per month
• Internship: Internship stipend (gratification de stage) in line with French law

Language: English required, French a plus (not mandatory).

About Bloomineral

Bloomineral is building a carbon-negative materials platform based on a biomineralization process.

We take CO₂, industrial waste, and seawater, and transform them into solid mineral forms that can be used in industrial materials, replacing emissions-intensive inputs with carbon-storing alternatives.

We’re an early-stage team based in Paris. Our current focus is simple: make the science work in real systems and make it scale.

What you’ll do

Help turn our systems into something that can scale.

You’ll contribute to the design, construction, and operation of our pilot system. The focus is on conceiving systems that are functional, stable, and ready for scale.

You’ll work within our R&D team to build physical systems with measurement and control. The level of ownership will be adapted to your profile and experience.

Responsibilities

• Design or support the design of reactors and fluid systems for the pilot systems (lab + shipping container), as well as tools developed for the R&D team. CAD will be required to communicate our plans to contractors.
• Contribute to modelling, including basic chemistry and thermodynamics, mass transfer, and heat transfer.
• Support automation and control, including sensor integration, data acquisition, feedback loops, Raspberry Pi, and related systems.
• Build the system: you will source components and contribute to or lead fabrication, depending on your experience. We know what we need, it works on the bench, and we now want the continuously operating version.

Profile

For an internship:

• Engineering student in mechanical, chemical, structural, or another relevant multidisciplinary field
• A valid convention de stage covering the full internship period is required
• Strong fundamentals in mechanical design, fluid dynamics, structures, and electronics; hands-on DIY, building, or prototyping experience is highly valued
• Familiarity with modelling tools, CAD, or simulation environments
• Based in Paris or able to relocate immediately

For a CDD:

• Engineer in mechanical, chemical, structural, or another relevant multidisciplinary field
• Relevant hands-on experience in mechanical design, prototyping, pilot systems, industrialization, or a closely related area
• Able to work with a high level of autonomy and take ownership from design through fabrication and operation
• Strong fundamentals in mechanical design, fluid dynamics, structures, and electronics
• Proficiency with modelling tools, CAD, or simulation environments
• Based in Paris or able to relocate immediately

For both profiles:

• Interest in bioproduction is a plus
• Creative, detail-oriented, a clear communicator, and comfortable learning quickly in a multidisciplinary environment

Why this role

You’ll work on real systems with real constraints, not theoretical projects, and with real living organisms performing the mineralization.

This is a chance to gain hands-on experience with pilot-scale infrastructure and see how engineering decisions translate directly into system performance. You’ll be involved from design through to operation.

You’ll join a small, technical, highly international team where everyone takes high ownership, with exposure to process engineering, biology, and geochemistry in a single system. Both contract options have the potential to develop into a permanent position.

We care more about curiosity, rigor, and drive than about checking every box. If our mission resonates with you but your profile doesn’t match every single line above, apply anyway. If you do not yet know electronics, for example, and can find an expert to help you learn, we will support you but we need you to be 1000% motivated.

We’re building a diverse, thoughtful team and we know great people don’t all look the same on paper. If you’re excited about turning carbon into materials the world can build with, we’d love to hear from you.