If you'd like to change the validation message from "Primary Affected Service is required" to "Service concerné primaire est nécessaire".
Some of you may try to invent a new mechanism to do it. And in this artical, I'm going to show you how to do it with build-in method in 3 steps:
First of all, you need to define a validation Rule, for example, in Out-of-Box (OOTB), the Ruleset im.standard.mandatory includes followling Rule to validate the mandantory of "Primary Affected Service":
Then you need to localize the message "Primary Affected Service is required". Actually this message is composited like below:
To localize the message, you need to add a new record in scmessage like below:
To localize the field caption, you need to add another new record in scmessage like below:
Then when you login as French, your validation message will display like below: