When do you usually register a trademark for a new SaaS — before or after market validation?

I’m an independent developer based in France and I currently have a few SaaS products at different stages.

For one product, the brand is already decided and I’ve filed a trademark application.

For two others, the products are not fully validated yet. My plan is to first reach out privately to potential business customers, get some early users or paying customers, and see whether there is real demand before investing more heavily in the brands.

The names would still be checked beforehand for obvious trademark conflicts, domain availability, and existing companies/products.

I’m wondering how other founders handle this:

• Do you file a trademark before doing any customer validation?

• Or do you first validate the product with a small number of customers and only register the trademark once you know you want to keep the product and the name?

• At what point do you personally feel that waiting becomes risky?

• For founders in France or the EU, has anyone had problems because they waited until after getting their first customers?

• Would you treat private B2B outreach differently from a public launch or paid marketing campaign?

I’m not asking whether a trademark is legally required to launch. I’m mainly interested in the practical founder perspective: balancing brand protection against spending money too early on a product that might still change or be abandoned.

Would be especially interested to hear from people who have launched several small SaaS products.