Building a Bilingual Website (NL/FR) for the Belgian Market

Building a bilingual website for the Belgian market does not start with the technology, but with a commercial question: are you truly serving a French-speaking market, or does a second language mainly add work and maintenance? Only when the answer is “yes, French belongs to our plan” do the choices about URL structure, default language and translation scope start to matter. This article walks through those strategic decisions, separate from the pure code, so that you build a site that generates leads in two languages instead of two half sites that get in each other’s way.

When do you really need a French version?

You need a French version when French-speaking Belgium or France is a deliberate part of your target audience and your sales plan, not because “it is expected in Belgium”. That distinction determines whether a second language becomes an investment or a ball and chain.

Belgium has four language regions: a Dutch-speaking Flanders, a French-speaking Wallonia, a small German-speaking community and bilingual Brussels, where Dutch and French are equivalent. For commercial communication, freedom of language use largely applies: you may in principle address your customers in the language that suits your market. As an ordinary B2B company, you therefore usually have no legal obligation to be bilingual. The question is purely commercial.

Ask yourself three honest questions. Is there already concrete demand from Wallonia or Brussels, or do you only suspect it? Can your team actually follow up French-speaking leads in French, from quote to invoicing? And does the extra revenue outweigh the permanent maintenance of a second language version? If the answer is three times “yes”, then French is justified. If you are in doubt, a tidy single-language site that converts is almost always better than two half sites. Where to start concretely when you do enter that market is covered in entering the French-speaking market with your website. How to build a site that already generates leads on its own is covered in our guide on B2B website development.

Which URL structure do you choose for a bilingual site?

For most Belgian B2B companies, a subdirectory structure is the best choice: example.be/nl/ and example.be/fr/ on the same domain. You keep all your authority on one domain, management is simple and the structure is crystal clear for search engines.

There are roughly three options, each with its trade-off:

• Subdirectories (example.be/nl/, example.be/fr/): simple, all SEO value stays on one domain, and it is cheap to maintain. For virtually every Belgian B2B site, this is the default choice.
• Subdomains (nl.example.be, fr.example.be): sometimes handy if the two versions are managed by separate teams or systems, but search engines partly treat subdomains as separate sites, so you split your authority.
• Separate country domains (example.be and example.fr): only worthwhile if you truly serve different countries with their own entities, for example Belgium and France separately. It is the most expensive to manage and builds authority per domain.

For a Belgian company that simply wants to serve NL and FR within Belgium, the subdirectory approach is the smartest in nine out of ten cases. Important: let the URL slugs match the language of the content, so /nl/diensten/ and /fr/services/, not /fr/diensten/. That consistency helps both visitors and search engines and fits a clean website architecture for SEO.

How do you choose which language is the default?

The default language is the language of your largest or most important market, and when in doubt the language in which the most leads come in. For a typical Flemish company that is Dutch; for a company centred in Brussels or Wallonia it can be French.

A common mistake is automatically redirecting based on the browser language or the visitor’s IP address. That feels clever, but it often backfires: a French speaker who deliberately opens your Dutch page gets sent away, and search engines crawling your site end up in a wrong or inconsistent version. It is better to put each language version on a fixed, findable URL and let the visitor choose for themselves with a clear language switcher in the navigation. Place that switcher prominently, use the language name in its own language (“Nederlands”, “Français”) and preferably have the choice land on the same page in the other language, not on the homepage.

For search engines, you additionally indicate which version is the fallback for visitors without a clear language preference. You arrange that technically with hreflang, including an x-default. How exactly that works is covered in the article on hreflang tags for Belgium.

Should you translate everything or only what converts?

No, you do not have to translate everything. Start with the pages that actually generate leads and only expand once the second language proves itself. A full translation upfront is expensive and is often largely wasted while the French-speaking market still has to be proven.

A pragmatic order for a first French version:

1. The core pages: homepage, your most important service pages and the contact page. This is the minimum with which a French-speaking lead can take you seriously and get in touch.
2. Proof and trust: an about page and possibly references or cases, because trust is often the bottleneck in B2B.
3. Deeper content: blog articles and knowledge base you only translate once the first layer pays off.

When translating, pay attention to more than the words. A good French version is localized: amounts, VAT logic, examples and references that are correct for that market. Preferably have business texts reviewed by a human, because a form or call to action that sounds just slightly off costs you conversions. Machine translation can speed up a first version, but do not publish it uncorrected on pages that are meant to make money. Honest advice here: better three strong French pages than thirty mediocre ones.

Where do bilingual B2B sites get stuck in practice?

The biggest pitfall is maintenance: a second language version is not a one-off project but a permanent commitment. Every new service, price change or campaign now has to be applied twice, otherwise one of the versions falls behind.

Common problems we see in practice:

• Half-finished translations: a Dutch button or error message in the middle of a French-speaking page. That undermines your credibility more than a correct single-language site.
• Orphaned versions: the French site is no longer updated after launch and slowly drifts out of sync.
• Lost positions during a migration: if you convert a single-language site to bilingual, you often change your URL structure. Without clean redirects you lose rankings. Plan that carefully, as described in website migration without losing rankings.

Also take accessibility into account. Since 28 June 2025, the European Accessibility Act applies, which imposes digital accessibility requirements on certain products and services. For purely B2B services, that falls outside the strict obligation in many cases, but as soon as you also sell to consumers or offer e-commerce functions, it can come into play. Have this legally assessed on a case-by-case basis and build in accessibility well anyway, because it makes your site more usable for everyone. Whether your Belgian site falls under it and is compliant is covered in the European Accessibility Act for Belgian websites. Which mistakes to avoid in doing so is covered in web accessibility mistakes.

The short summary

Building a bilingual website for Belgium is first and foremost a strategic choice, not a technical one. First confirm that a French-speaking market truly belongs to your sales plan. Then, in most cases, opt for a subdirectory structure on one domain, put each language version on a fixed URL with a clear language switcher, and only translate what converts before you expand further. Maintenance is the real cost: a tidy single-language site always beats two neglected half sites. If you want this worked out platform-neutrally and conversion-focused for your specific case, take a look at our approach to website development.

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