The 10 Best CRO and Conversion Agencies in France (2026)

The short answer

Conversion optimisation in France splits into three families: data and experimentation agencies that run structured test programmes, e-commerce agencies that rebuild stores around conversion, and landing page specialists who work at the point where an ad becomes a customer. Welyft ranks first because it covers the whole method, from user research to experimentation to training your own team, which is the only version of CRO that keeps working after the contract ends.

Here is the full ranking, with what each agency says it does and the situation it suits best.

1. Welyft. Data marketing and CRO, research through to experimentation. Best for a structured testing programme.

2. Lëc Media. A CRO agency working on Shopify stores. Best for an online store that converts badly.

3. Agence Shop. Shopify builds designed around conversion. Best for a store rebuild rather than a patch.

4. ConvertLab. Landing pages built for advertising campaigns. Best when the ads work and the page does not.

5. Arquen. User experience research and design. Best when you need to know why, not just what.

6. Moon Moon. Shopify Plus partner with a CRO practice. Best for larger Shopify brands.

7. Empirik. Conversion inside a wider data and search offer. Best when acquisition and conversion move together.

8. Zooka. Digital performance across acquisition and optimisation. Best for a full performance mandate.

9. Blue Bagels. Direct response creative and landing pages. Best for direct to consumer brands scaling paid.

10. Transacts. Turning search visibility into calls and quotes. Best for smaller companies selling services.

Why conversion work pays more than it used to

The arithmetic has not changed, but the context has. A page that converts at 2 percent instead of 1 doubles the return on every euro of acquisition you already spend, without buying a single extra visit. What changed is the price of those visits. When traffic was cheap, buying more was the easier answer. It is no longer the easier answer.

The second shift is that conversion work has become measurable in ways it was not five years ago, and also harder to measure. Consent rules cut into the data an agency can collect, so serious teams now pair experimentation with qualitative research instead of relying on volume alone.

The third is that the visitor arrives differently. Someone sent by an assistant that recommended you has already been half convinced by a third party, and lands with different expectations from someone who clicked an ad. Pages built for one audience often mishandle the other.

How we ranked these agencies

We used four criteria, in this order, and only what each agency publishes about itself.

1. Is conversion the subject? Agencies whose homepage leads with conversion optimisation come first, ahead of those where it is one service among fifteen.

2. Method, not just redesign. Research, hypothesis, test, measure. Agencies that name their method are easier to hold to it.

3. Where they work. A store, a landing page and a lead generation site are three different problems. We noted which one each agency actually addresses.

4. Whether the site is alive and clear. We looked at every homepage in our list, in August 2026, and removed the ones that would not render or no longer describe a marketing business.

We did not rank on uplift percentages. Almost every agency in this sector publishes one, none of them can be verified from the outside, and a ranking built on them would reward the boldest homepage rather than the best method.

The 10 best CRO and conversion agencies in France

1. Welyft

Welyft presents itself as a data marketing and CRO agency, with four named offers: conversion optimisation and continuous improvement, experimentation and derisking through A/B and user testing inside product discovery, data and analytics, and training to build an experimentation culture in your own teams. That last one is the tell of an agency that expects to make itself progressively less necessary.

Best for: companies that want a testing programme rather than a one off redesign.

2. Lëc Media

Lëc Media calls itself a CRO agency in its own page title and works as a Shopify partner: conversion optimisation, migration to Shopify, store development and redesign. The combination matters, because on an online store the honest answer to a conversion problem is sometimes a rebuild, and an agency that can only test is stuck recommending patches.

Best for: online stores where the conversion rate has stopped improving.

3. Agence Shop

Agence Shop builds Shopify stores with conversion as the stated design brief, and names a Shopify CRO audit and conversion oriented redesign among its services, including a line dedicated to premium and luxury brands. It sits closer to the build side than the testing side, which is the right order when the current store is the problem.

Best for: brands whose store needs rebuilding rather than tuning.

4. ConvertLab

ConvertLab is a landing page agency for advertising campaigns, with a stated B2B focus and separate offers for e-commerce and software landing pages. Its argument is simple and correct: a campaign and its destination page have to be written together, and sending paid traffic to a generic homepage wastes most of the budget.

Best for: advertisers whose campaigns are well built and whose landing pages are not.

5. Arquen

Arquen is a user experience design agency working from Paris and Lyon, structured around understanding before designing: user research, UX audits and ergonomic evaluation, then interface design. When a conversion problem resists testing, it is usually because nobody has asked the users anything, and this is the kind of agency that starts there.

Best for: products where the friction is not obvious and needs to be researched.

6. Moon Moon

Moon Moon is a Shopify Plus partner based in Nantes, covering migration, redesign, CRO, point of sale, CRM and interface design, with e-commerce brands as its stated client base. Partner status at that level matters mostly for one reason: access to the platform features that larger stores actually need.

Best for: established Shopify brands whose conversion work has to survive a complex catalogue.

7. Empirik

Empirik works from Paris and Lyon and lists conversion as one of five named practices, next to analytics and data, organic search and content, generative search, and paid search and social. The agency frames its whole approach around turning a company's own data into decisions, which is the same argument conversion work rests on.

Best for: companies that want acquisition and conversion argued by the same team.

8. Zooka

Zooka describes itself as a digital performance agency specialising in web optimisation, with a service list that runs across organic search by platform, paid search, shopping, marketplace advertising, social advertising, landing pages and retargeting. It is the broadest mandate on this list, which suits companies that would rather hold one supplier accountable for the whole funnel.

Best for: companies wanting acquisition and optimisation under one contract.

9. Blue Bagels

Blue Bagels is a direct response creative agency working with direct to consumer brands, producing static and video ad creatives, advertorials and landing pages, and describing its work as built on a large body of A/B tests. The offer is a full funnel rather than a page, which is the correct unit when paid traffic is the only source.

Best for: direct to consumer brands scaling paid acquisition.

10. Transacts

Transacts is a Paris digital agency operating since 1999, and states its objective in business terms rather than marketing ones: more calls, more quotes, more customers for smaller companies, through search engines and AI assistants. Its three stated pillars are visibility, automation and conversion, which is the right sequence for a service business.

Best for: service companies whose conversion is a phone call or a quote request.

Other agencies worth knowing

These firms also work on conversion, measurement and customer journeys in France. Most sit closer to data consulting or e-commerce development than to a dedicated CRO practice, which is why they are here rather than in the ranking.

What to check before you sign

Three questions separate a conversion programme from a redesign with a nicer name.

1. What happens when a test loses? Half of them will. A serious agency has a documented answer, keeps the losing variant as evidence and tells you what it learned. An agency that only reports winners is reporting selectively.

2. Who decides what gets tested? If the backlog comes from opinions in a meeting, you are paying for taste. It should come from research, analytics and recorded friction.

3. Which metric closes the test? Clicks on a button are easy to move and often move revenue in the wrong direction. The metric should be the one your business is actually paid on.

Conversion has a ceiling, traffic quality does not

Every conversion programme eventually meets the same wall. You can improve a page until it is genuinely good, and then the remaining variable is who is arriving. A visitor who came looking for something else will not convert on any version of the page.

That is why the most durable conversion gains often come from upstream: attracting people who already understand what you sell and why. Someone who read your article on the problem, or who arrived because an assistant recommended you by name, converts at a rate no button colour will ever reach.

That is what Sorank automates. It is software, not an agency: keyword research, article writing, internal linking, publishing to your site and tracking how often you appear in the answers AI assistants give. Pricing starts at 99€ per month, with 3 days offered and a card required at sign up. If you would rather talk it through first, book a call.

Conclusion

If you want one recommendation: Welyft for a real experimentation programme with your team learning along the way, Lëc Media or Agence Shop if the problem is an online store, and ConvertLab if your advertising is fine and your landing pages are throwing the budget away.

Whichever you choose, agree the metric before the first test. Almost every disappointing conversion engagement ends in the same argument, and it is always about what should have been measured.