Bonsoirs: How Full-Funnel Measurement Revealed 83% of Hidden Channel Value and Unlocked Confident Scaling

The Challenge

Like many DTC brands, Bonsoirs had built its measurement around Last Click. Brand Search and Shopping looked healthy. Paid Social - Meta, Pinterest, TikTok - appeared well below breakeven. This is the structural trap Last Click creates. Impression-led channels rarely receive the final click before a purchase. Instead, they create the demand that converts later through Direct, Organic Search, or Brand PPC. Demand-generating channels get almost no credit, while demand-capturing channels absorb it all.

Without a trusted view of what was actually working, decisions were deferred, Bonsoirs' executive team couldn't justify scaling brand investment, and measurement was becoming a source of friction rather than confidence.

The Solution

When Bonsoirs began working with Fospha, the first insight was immediate. Fospha's always-on, impression-led Media Mix Model, updated daily and down to the ad level, revealed a fundamentally different picture of full-funnel performance. Across Paid Social, Demand Gen and YouTube, Last Click was capturing just 17% of their true contribution and hiding 83% of their real value.

The breakdown by channel:

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The channels Bonsoirs had been cautious about were, in reality, among their strongest performers. Fospha helped provide this cross-channel visibility, enabling them to identify new scaling opportunities and justify increased spend across these channels.

Year-over-year, Bonsoirs achieved a +5% ROAS improvement at a blended level and a +10% ROAS uplift in Paid Social, evidence that the team was able to scale their key growth channels while simultaneously improving efficiency. Across the portfolio, spend increased meaningfully into the channels Fospha identified as undervalued, with returns improving rather than diminishing as investment grew.
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Channel-Specific Highlights

• Meta remained the primary Paid Social channel, scaling spend YoY while improving Fospha ROAS - despite Last Click reflecting only a fraction of its true contribution.
• Pinterest emerged as one of the most efficient channels in the portfolio, with the strongest ROAS improvement YoY.
• TikTok demonstrated clear scalability, with the largest spend increase across Paid Social and continued ROAS growth.
• On the Google side, both Demand Gen and YouTube saw significant spend scaling with stable Fospha ROAS, validating the team's move toward always-on upper-funnel investment across platforms.
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"We're very happy with the valuable insights Fospha provides - the platform's measurement capabilities allow us to compare ROAS across channels, providing insights into underperforming areas like branding and reach campaigns on Meta and YouTube. We also utilize Fospha's granular reporting down to the ad level to better understand performance differences between ads for the same products." – Alexandre Ackermann, Head of Growth, Bonsoirs

The Bottom Line

Bonsoirs' measurement had been telling them to pull back on their strongest growth channels. By replacing Last Click with Fospha's always-on, full-funnel measurement, the team uncovered that 83% of their demand-generating channels' true value was invisible - and used that insight to scale with confidence. The result: improved efficiency at both blended and paid level, with Paid Social ROAS growing +10% YoY even as spend scaled significantly.

For brands still relying on click-based attribution to make budget decisions, Bonsoirs' story illustrates what's at stake - and what becomes possible when measurement reflects how demand is actually created.

Footnotes

Impact Type: Blended and paid media impact.

‍Time Range & Period Comparion: Year-over-year (Apr 2024 – Feb 2025 vs. Apr 2025 – Feb 2026).

Markets Analyzed: France (FR).