Unifying Yon-Ka Paris Across Continents

Established in France in 1954 by the Mühlethaler family, Yon-Ka Paris is a pioneer in the realm of professional, plant-based skincare. Built on the principles of phyto-aromatherapy, the synergistic combination of essential oils and active plant extracts, the brand masterfully bridges the gap between scientific efficacy and multi-sensory wellness. At the core of Yon-Ka’s formulation philosophy is their signature “Quintessence,” an exclusive therapeutic blend of five Mediterranean essential oils: lavender, rosemary, geranium, cypress, and thyme. Known for its luxurious, holistic spa treatments and dermatologist-approved home care regimens, Yon-Ka Paris continues to innovate from its world-class facility near Paris, offering clean, sustainable, and highly personalized skincare that revitalizes both the skin and the senses.

A Heritage Brand Ready for Global Scale

For over 70 years, Yon-Ka Paris, owned by Multaler et Cie, has been synonymous with professional-grade skincare, trusted by spas and skincare professionals across four continents. Behind the brand’s reputation for quality sits a manufacturing operation of considerable complexity: cosmetics produced to pharmaceutical-grade standards, a network of five international subsidiaries, third-party logistics across France and the UK, and multiple digital storefronts serving distinct markets.

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When Alexis Wolkowinski, President of Yon-Ka, set out to modernize the technology backbone of the business, the goal was clear: replace a patchwork of legacy systems with a single platform capable of connecting every part of the value chain, from raw material receipt at the Paris facility to customer delivery confirmation in New York, London, or Geneva.

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“We needed more than a system upgrade. We needed a foundation that could grow with us.”

Alexis Wolkowinski | President, Yon-Ka Paris

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Choosing Odoo: Conviction Over Convention

Yon-Ka already knew the cost of the reflexive answer. Between 2017 and 2020, headquarters pursued the conventional path, a large-scale enterprise-cloud implementation whose price tag was meant to buy certainty. It bought the opposite: after years of effort and millions committed, the programme was abandoned without ever going live, and the company’s stability was put at risk.

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So when Antoine Lamarche, CEO, revisited the question, he asked a harder one than “which ERP is safest to buy?”, namely, “which platform can actually reflect how this company works, and grow with the people who run it?”. Rather than trust analyst rankings, he sought out owners in South America, Florida, Canada, Northern Europe and Hong Kong already running Odoo. Their verdict was consistent: rare flexibility, genuine value, a system that adapts to the business rather than the reverse. Odoo could model Yon-Ka’s real complexity, pharmaceutical-grade manufacturing, five subsidiaries, four currencies, multiple storefronts, without imposing someone else’s idea of how a cosmetics house should operate.

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The rest was people. Antoine built belief on both sides of the Atlantic, aligning New York and Argenteuil behind one source of truth. What set Gray Matter Logic apart was its own team, whose down-to-earth expertise carried every user through go-live and beyond. And above all, it was Cédric Geffroy, who became the system’s strongest believer, went deep enough to become an Odoo expert himself, and today trains and mentors every user, reworking processes so the system truly serves their daily work.

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“I didn’t want the safe logo. Every big name would have sold us reassurance and asked us to rebuild the company around their software, we had tried that once before, at enormous cost. What convinced me this time were the owners already running Odoo and delighted with it — and then Greg, Max, and Daniel, who cared about every single user, not just the system. That’s a bet on people and on the future, not on a brand.”

Antoine Lamarche | CEO, Yon-Ka Paris

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The Challenge: Complexity Worthy of a Tailored Approach

Cédric Geffroy, CTO and the project’s internal champion, understood the scope of what it would take. The challenge was not one problem, it was five simultaneous problems that had to be solved as one.

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1. A non-negotiable deadline

For Antoine Lamarche, CEO, the decision to move to a unified ERP was not simply a technology choice, it was a strategic commitment. The business had outgrown its legacy ERP system, which had reached end-of-life, leaving a hard deadline that could not slip. Phase 1, replacing the outdated, obsolete, and unstable accounting software, was completed on a very tight timeline, before the end of the fiscal year. More fundamentally, Yon-Ka needed its systems to reflect how it operates: globally, with precision, and without compromise on quality.

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2. Pharmaceutical-grade manufacturing traceability

Multaler’s MIP industrial production department manufactures cosmetic formulas and finished goods subject to strict lot traceability and quality control requirements. Any solution needed to enforce supplier approval processes, lot locking workflows, QC release gates, and audit trails aligned with GMP Annex 11 principles, while managing hazardous raw material storage constraints.

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3. Multi-subsidiary intercompany complexity

Yon-Ka’s five subsidiaries across the US, UK, Belgium, Switzerland, and Germany each purchase from the French parent. Each had distinct invoicing requirements, individual per-shipment invoices for the UK, monthly consolidated invoices for continental Europe, and required dropship delivery flows managed at the head-office level.

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4. A real-time warehouse integration

Warehouse operations at Argenteuil are managed by a specialist WMS. The integration needed to be bi-directional and real-time: transmitting sales orders, picking instructions, resupply transfers, and shipment confirmations, including lot numbers, tracking data, and pallet information, without any manual intervention.

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5. Pricing complexity at scale

Over 15 price lists across four currencies (USD, GBP, CHF, EUR) serving distributors, subsidiaries, B2B direct customers, and Shopify B2C channels, each with individual per-product pricing, minimum full-box ordering rules, and year-end rebate mechanisms.

The Gray Matter Logic Approach: Process First, Not Software First

Gray Matter Logic’s engagement began long before any configuration work. The team invested in understanding how Yon-Ka’s operations actually ran, from the rhythm of the MIP production floor to the nuances of intercompany invoicing across jurisdictions. The principle that guides every Gray Matter Logic engagement, process first, not software first, proved especially relevant here.

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The result was a phased architecture that allowed Yon-Ka to build confidence incrementally, rather than attempting a single high-risk cutover. Each phase delivered real value before the next began, and the three-phase structure meant that teams could validate workflows in their own context before they went live.

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Six functional domains were configured and delivered across the engagement:

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1. Sales & Marketing: unified B2B order management, intercompany subsidiary sales, multi-pricelist enforcement, and direct WMS shipment note transmission.

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2. Manufacturing: multi-step production for Solutions, Formulas, and Finished Goods, with GMP-aligned lot locking, QC release workflows, GS1 label printing, and a Master Production Schedule.

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3. Inventory & Logistics: 2-step receiving, hazardous material put-away rules, 3PL resupply flows, and Swiss dropship consolidation, all orchestrated through the WMS connector.

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4. Purchasing: supplier approval workflows, automatic intercompany PO creation, and subcontracting flows for primary and secondary conditioning.

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5. E-Commerce: four Shopify storefronts connected post-go-live, with automatic order import, tracking number propagation, and dropship triggering for the Swiss channel.

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6. Finance & Accounting: fiscal position-based revenue mapping, multi-currency invoicing, consolidated billing for European subsidiaries, and full intercompany reconciliation across six legal entities.

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The Journey: from Concept to Go-Live

What follows is not just a project timeline, it is the story of how a team built trust through transparency, resolved hard problems in real time, and delivered a working system under genuine pressure.

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Phase 1 · 2024: Laying the Financial Foundation

Establishing the European accounting core at Multaler et Cie: chart of accounts, fiscal positions, and intercompany structures.

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Phase 2 · 2024–2025: Expanding to the US

Full ERP implementation for the US subsidiary: accounting, purchasing, sales, Magento and Shopify connectors, inventory and warehouse operations with Zebra barcode portable devices.

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Phase 3 · 2025–2026: Back to Europe for Operations, Purchasing and Sales

Rolling out Planning, Inventory, Manufacturing, Subcontracting, Purchasing and Sales across France and all European subsidiaries, a complex pharmaceutical-grade manufacturing setup, integrating three further subsidiaries with accounting, purchasing and sales, plus a dropship mechanism for subsidiary orders shipped from the French HQ.

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Go-Live · Mar 2026: Production Go-Live, March 9

Two “war rooms” were established for the go-live: one covering sales and accounting, the other manufacturing and purchasing, while Cédric Geffroy orchestrated warehouse operations alongside the Gray Matter Logic team.

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Hypercare · Apr 2026: Stabilization & Shopify Rollout

A dedicated on-site stabilization and improvement week: advanced manufacturing planning, advanced instant inventory valuation, multiple Shopify integrations, and CRM deployment.

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The go-live was the result of various production releases deployed in the final three weeks, with Gray Matter Logic’s on-site team alongside Cédric Geffroy, refining the WMS integration, finalizing data migration, and stabilizing all modules for day-one operations.

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“The on-site presence was critical before, during, and after go-live; from the workshops and mock go-live, to the production launch and the hypercare week. That continuity made all the difference. When issues came up, they were resolved in hours, not days or weeks.”

Cédric Geffroy | CTO, Yon-Ka Paris