In e-commerce, a limited number of commercial moments shape the year. Sales periods, Black Friday, French Days, year-end promotions, product launches and clearance events account for a significant share of visibility, acquisition and conversion.
By the time a transaction takes place, much of the work has already been done. Shoppers browse, compare, build baskets and return multiple times. Decisions emerge gradually, across several visits, well before the point of purchase. It is during this upstream phase that consent becomes a strategic factor, as it determines how much data can be used later on and how reliable that data will be once campaigns are running.
As competition tightens, driven in particular by the growth of second-hand marketplaces and evolving consumer habits, access to trustworthy and usable data has become a decisive differentiator for targeting, personalisation and performance measurement.
It is from this perspective that Axeptio and Agence123 chose to co-author an original white paper. Based on six implementations, it examines how a tailored cookie banner can sharpen the customer journey, support brand perception, improve measurement and attribution, and help marketing teams operate with more reliable data during periods of heightened commercial activity.
Beyond designing and optimising e-commerce platforms, Agence123 supports brands through a strong pedagogical role: translating regulatory requirements into concrete choices, balancing UX constraints, safeguarding technical performance, and deploying consent management platforms that comply with GDPR, foster trust and sustain opt-in.
Drawing on six implementations carried out with Axeptio, this white paper shows how consent can move past compliance to operate as a true marketing performance lever. It highlights different cookie banner and consent wall strategies, adapted to distinct sectors, customer journeys and conversion objectives, with consent rates reaching up to 85%.
This case study also explores how consent affects measurement, attribution and data modelling (notably through Google Consent Mode v2) and how preparing the CMP ahead of traffic peaks can help stabilize campaign performance without degrading the user experience. The study finally opens onto emerging perspectives for 2026, with video becoming both a first interaction and a new space for brand expression within the consent experience.
“The opt-in rate is the most strategic KPI because it determines how much data can actually be used for campaigns. Low opt-in distorts attribution, weakens audience quality and limits platforms’ ability to optimise. When consent rates increase, measurement, targeting and ROAS improve mechanically. That’s why we treat the CMP as a performance lever in its own right, not just as a technical prerequisite.”— Jordan Attia, Digital Marketing Manager, Agence123
Download the white paper using the form and turn your cookie banner into a lever for both performance and brand perception.
