Freelancer profile translated to English.
Back to original languageAbout Mikael
A critical incident in production? An Exchange, Microsoft 365, or Active Directory migration to secure? A need for expert support on complex Microsoft infrastructures?
With 15 years of experience (IT service companies, large accounts, public sector), I intervene on your critical environments: expertise, migration, MCO, L3 support, and technical leadership.
I have supported dozens of organizations (GHT, local authorities, private sector) with over 40,000 mailboxes migrated without service interruption.
🔹 Microsoft 365 & Identities
- Microsoft 365 / Office 365
- Microsoft Entra ID / AD Connect
- MFA, Conditional Access, and identity security
- Tenant audit and compliance
🔹 Exchange & Messaging
- Exchange Server (2007 to SE) & Exchange Online
- Hybrid architectures and mergers/consolidations
- Exchange & Tenant-to-Tenant Migrations
- L3 Support, critical incident management
- SPF, DKIM, DMARC, EOP
🔹 Active Directory & Infrastructure
- Active Directory (Migration, restructuring, consolidation)
- Windows Server, DNS, DHCP, RDS
- Two-tier Microsoft PKI (Root / Sub)
- Reverse Proxy, Load Balancer (Kemp, HAProxy)
- VMware & Hyper-V Virtualization
🔹 Run, MCO & Expertise
- Operational Maintenance & L3 Support
- Crisis management, complex incident diagnosis and resolution
- Backup and DRP (Veeam, AWS)
- Technical documentation (DAT / DIN / DEX, Procedures)
🚀Why contact me?
✔ 15 years of Microsoft infrastructure expertise
✔ +40,000 mailboxes migrated with zero data loss guarantee
✔ Specialist in Health Sector (GHT) and Local Authorities
✔ Dual expertise: Technical Expertise & Leadership (CDP)
✔ Flash interventions (emergencies) or long missions (contract)
📍 Hybrid in Loire-Atlantique. Remote across the rest of France.
French
Native or bilingual
English
Conversational
Can work on-site
Nantes (up to 50km), Paris (up to 50km), Vannes (up to 50km), Saint-Nazaire (up to 50km), La Roche-sur-Yon (up to 50km)
Experience
- SYSEXPERTMicrosoft & M365 Infrastructure Expert | IT Project Manager | Founder of SYSEXPERTDIGITAL AND ITJanuary 2026 - Today (5 months)Nantes, FranceDirect support for companies and IT service companies in securing, migrating, and managing (Run/MCO) critical Microsoft infrastructure and messaging environments.**Recent Interventions**:
- **Complex Cross-Forest Migrations (Exchange 2016 → 2019)**: Corporate 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 messaging flow security (SPF, DKIM, DMARC).
- GROUPE OPEN (Ile-De-France Mobilités)Technical Expert | Systems & Security Engineer (L3)DIGITAL AND ITApril 2025 - November 2025 (7 months)92300, Levallois-Perret, FranceIntegration into the Expertise team in a high-criticality large account environment.Key missions:
- **Run & L3 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, certificate and flow monitoring via Kemp and Retarus gateways.
- **Governance & Documentation**: Writing, updating, and maintaining technical architecture and installation files (DAT, DIN) according to production department standards.
- **Lifecycle**: 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, FranceProgressive evolution within the group, from Lead Technical Expert to overall management of transformation projects within the Project Management department (multi-client IT service company environment).Record: Over 40,000 mailboxes migrated and secured in the public, health (GHT), and private sectors without service interruption.
🔹 Project Management & Leadership (V-Cycle)
- **Technical Leadership**: Scoping, budgeting, milestone/cutover planning, and leading project and steering committees (Copil).
- **Management**: Staffing, monitoring, and technical support of a team of 20 expert collaborators.
- **Technical Architecture**: Assistance in defining target architectures (On-Premise, Hybrid & Cloud).
🔹 Major Migrations & Messaging References
- **On-Premise Exchange 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 & Hybridization Migrations**: Mairie de Ploërmel (Bluemind to M365 via Transend), Luc Durand (Exchange to O365), CH de Caen (O365 Hybrid architecture on a 3-tier infra).
🔹 Infra, Run & 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.
- **Run & Production**: AD/Exchange compliance audits, migration of critical roles (DHCP, NPS), and L3 crisis technical support.
Reviews
Ronan
Indépendant - Ronan Broussier EI
Reviewed on 4/29/2026
Michael assisted me with the migration of my Exchange and M365 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 on Mikael for his services. We are once again delighted. He is responsive, provides very relevant advice, and is a true professional. We particularly appreciated his availability. Thank you.
Recommendations
These freelancer profiles also match your criteria
Agatha Frydrych
Backend Java Software Engineer
4.7
(3)
2
Baptiste Duhen
Fullstack developer
4.6
(4)
5
Amed Hamou
Senior Lead Developer
4
(2)
7
Audrey Champion
Web developer
4.3
(3)
4
Education
- BTS in Management Information Technology2010BTS Informatique de Gestion
Certifications
- Microsoft 365 Certified: Messaging Administrator AssociateMicrosoft MS-2032023
- Office 365 AdministrationMicrosoft 70-3232015