diff --git a/doc/TP_experimental_biologists.md b/doc/TP_experimental_biologists.md
index 5d72a3819a88e59e9022056933c10c424ec8d81d..f3291091d04cceb37f7df65bdf6e3117a5e6e7d8 100644
--- a/doc/TP_experimental_biologists.md
+++ b/doc/TP_experimental_biologists.md
@@ -26,7 +26,7 @@ You are going to build a pipeline for you or your team. So the first step is to
 ## Forking
 
 Instead of reinventing the wheel, you can use the [pipelines/nextflow](https://gitlab.biologie.ens-lyon.fr/pipelines/nextflow) as a template.
-To easily do so, go to the [pipelines/nextflow](https://gitlab.biologie.ens-lyon.fr/pipelines/nextflow) repository and click on the [**fork**](https://gitlab.biologie.ens-lyon.fr/pipelines/nextflow/forks/new) button.
+To easily do so, go to the [pipelines/nextflow](https://gitlab.biologie.ens-lyon.fr/pipelines/nextflow) repository and click on the [**fork**](https://gitlab.biologie.ens-lyon.fr/pipelines/nextflow/forks/new) button (you need to log-in).
 
 ![fork button](img/fork.png)