Freelancer profile translated to English.
Back to original languageAbout Mikael
Need expert support to structure, secure, and manage your Microsoft infrastructures long-term?
With 15 years of experience in critical environments, I act as an architect and technical lead to ensure the stability and performance of your IT systems.
I am not a "one-shot" provider; I integrate with your teams to transform your IT system with confidence.
Why engage me for a long-term mission?
- Dual expertise: I master both technical depth (AD, PKI, Exchange, M365) and project management. I bridge the gap between your business needs and technical reality.
- Architect's vision: Beyond day-to-day operations, I anticipate the evolution of your infrastructures to reduce technical debt and prevent critical incidents.
- Expertise in complex situations: Experienced in the Healthcare sector (GHT / CH), I know how to operate in high-criticality contexts with a rigorous and documented approach.
My preferred areas of intervention:
- Transformation management: IT modernization, hybrid solutions, AD restructuring
- Security: M365 tenant audits, access hardening (Entra ID, Conditional Access, ...), compliance
- L3 Technical Expertise: Complex incident resolution, critical support, expert maintenance
I am looking for support missions of 6 months or more to bring lasting added value to your IT teams.
French
Native or bilingual
English
Conversational
Can work on-site
Nantes (up to 50km), Vannes (up to 50km), Saint-Nazaire (up to 50km), La Roche-sur-Yon (up to 50km)
Experience
- SYSEXPERTFounder of SYSEXPERT & Expert ArchitectDIGITAL AND ITJanuary 2026 - Today (6 months)Nantes, FranceStrategic and operational support for companies in modernizing their Microsoft infrastructures.I act as an independent expert to secure, migrate, and sustain critical environments, combining technical expertise with project vision.**Recent Interventions**:
- **Complex Cross-Forest Migrations (Exchange 2016 → 2019)**: Company merger context with Office 365 interconnection, identity synchronization, and guaranteed total service continuity.
- **Infrastructure Modernization**: Exchange 2010 to Exchange SE migration to ensure vendor support.
- **Architecture & Security**: M365 tenant audits, access hardening (MFA, Conditional Access), and email flow security (SPF, DKIM, DMARC).
- GROUPE OPEN (Ile-De-France Mobilités)Technical Expert (N3 Architect)DIGITAL AND ITApril 2025 - November 2025 (7 months)92300, Levallois-Perret, FranceExpert support mission within an expertise unit for a large, high-criticality client.I served as the technical guarantor for the operational maintenance (MCO) and security enhancement of Windows Server and Microsoft 365 infrastructures.Key Missions:
- **Run & N3 MCO**: Administration, operational maintenance, and evolution of Windows Server and Microsoft 365 production infrastructures, implementation of a two-tier PKI (Root / Sub).
- **Cybersecurity**: Proactive risk management, Defender / E5 hardening, monitoring of certificates and traffic via Kemp and Retarus gateways.
- **Governance & Documentation**: Drafting, updating, and maintaining technical and installation documentation (DAT, DIN) according to production department standards.
- **Lifecycle Management**: Performing updates, version upgrades, and server decommissioning.
- Groupe AISInfra & M365 Expert | Technical Project ManagerDIGITAL AND ITFebruary 2022 - April 2025 (3 years and 2 months)Saint-Herblain, FranceExpertise and technical leadership on global transformation projects within an IT services company.Technical referent for large-scale migrations and complex infrastructures, primarily for the Healthcare (GHT) and public sectors.Track Record: Over 40,000 mailboxes migrated and secured in public, healthcare (GHT), and private sectors without service interruption.
🔹 Project Management & Leadership (V-Model)
- **Technical Direction**: Scoping, budgeting, milestone/cutover planning, and leading project and steering committees (Copil).
- **Management**: Staffing, monitoring, and technical support for a team of 20 expert collaborators.
- **Technical Architecture**: Assisting in defining target architectures (On-Premise, Hybrid & Cloud).
🔹 Major Migrations & Email Solutions
- **Exchange On-Premise Migrations (2007 → 2019)**: GHT d’Armor, GHT Brocéliande (via Quest), CH de La Rochelle, CH de Niort, CH des pays de Morlaix, CH Georges Mazurelle, CH Bretagne Sud, Nexecur, CESAME, CG56.
- **Cloud Migrations & Hybridization**: Mairie de Ploërmel (Bluemind to M365 via Transend), Luc Durand (Exchange to O365), CH de Caen (O365 hybrid architecture on a 3-tier infrastructure).
🔹 Infra, Operations & Security Expertise
- **Microsoft PKI**: Full deployment of 2-tier certificate infrastructures (Root and Intermediate Authority).
- **Perimeter Security**: Deployment of Reverse Proxy / Load Balancer (Kemp / HAProxy) with WAF feature activation.
- **Operations & Production**: AD/Exchange compliance audits, migration of critical roles (DHCP, NPS), and N3 crisis technical support.
Reviews
Ronan
Indépendant - Ronan Broussier EI
Reviewed on 4/29/2026
Michael assisted me with the migration of my Exchange and 365 account. This was done with speed and professionalism. I recommend.
D
Dominique
GERANT ECO LIFE GROUP - ECO LIFE GROUP
Reviewed on 4/18/2026
This is the second time we have called upon Mikael for his services. We are once again delighted. He demonstrates responsiveness, provides very relevant advice, and is a true professional. We particularly appreciated his availability. Thank you.
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Education
- BTS in Management Information Technology2010BTS Informatique de Gestion
Certifications
- Microsoft 365 Certified: Messaging Administrator AssociateMicrosoft MS-2032023
- Office 365 AdministrationMicrosoft 70-3232015