Loyal or non-loyal, a tailored mechanic for each: how Milka MMMax personalised its back-to-school retail media activation

A long-term partnership

‍This campaign is part of a three-year collaboration between Lucky cart, Mondelēz and Publicis — with its three agencies Spark, Publicis Commerce and Publicis Connected Media — built to address the Group's business challenges through retail media.
The back-to-school season 2025 presented a particularly demanding context for Mondelēz: supporting a premium range with a limited number of SKUs, during a period of intense promotional activity, while integrating a 360° plan spanning TV, social media, in-store, CRM and Drive. Retail media was expected to act as a bridge across all these channels.

Two mechanics, one business objective‍

The campaign's central innovation lies in the real-time segmentation of the Carrefour customer base using a purchase history criterion: any shopper who had bought a Milka product in the three months prior to the campaign was identified as "loyal"; all others were classified as "non-loyal". This segmentation, based on Carrefour's first-party data, operated automatically at login and triggered the mechanic best suited to each profile.
Loyal shoppers were offered a chance to meet Katy Perry or win concert tickets, directly capitalising on the global partnership between the pop star and Milka MMMax. Non-loyal shoppers, meanwhile, could win a €100 gift voucher, with a variable eligibility threshold calculated upstream through profile scoring — maximising incremental sales while encouraging trial of the MMMax range through an additional chance to win.
Both mechanics were deployed across the same strategic placements along the shopper journey — homepage, promotions page, product category pages (chocolates & confectionery, milk & plant-based drinks, soft drinks), search results and a dedicated "shop-in-shop" brand page — ensuring maximum visibility throughout the shopper's browsing session.

A unified operation through cross-redirection‍

Beyond on-site personalisation, the campaign stood out through the bridges built between Mondelēz's marketing channels. Carrefour banners redirected shoppers to Mondelēz's CRM platform Ma Vie En Couleurs to enter the Katy Perry competition.
In the other direction, banners and newsletters from Ma Vie En Couleurs redirected users to the Carrefour activation. This virtuous loop between the two ecosystems generated real synergy, with traffic flows in both directions and email open rates above the 2025 benchmark.

Results that confirm the power of personalisation‍

Over 23 days of campaign, the results demonstrate the effectiveness of a truly profile-based differentiated approach: 680,000 impressions generated, €72,000 in incremental sales, a €3.9 ROI, and 85% of sales driven by new or reactivated customers.
In terms of market share, the campaign contributed to a +0.7 percentage point gain in Drive market share, with sales up +138% in value and +126% in volume at equivalent promotional pressure vs. the prior year.

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An activation that proves first-party data, combined with a gamified and personalised mechanic, is now one of the most powerful levers for reconciling brand awareness with measurable commercial performance.

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