Look at this previous post:
https://forums.adobe.com/thread/1506686
To modify the script to your form, you could try this as the custom validation script for your combo box:
if (event.value=="Utilisateur") {
this.getField("OJV_OFFICE_UTILISATEURS").value = "Yes";
this.getField("OJV_OPF Caissiers").value = "No";}
else if (event.value=="Comptable") {
this.getField("OJV_OFFICE_UTILISATEURS").value = "No";
this.getField("OJV_OPF Caissiers").value = "Yes";}
Make sure you have the "Commit selected value immediately" option selected.