Translation issue with phone number validation

Hi,
I am working on translation in ERPNext and API.

I find that in respective User Form, i can change the language. By which entire text in the ERP core doctype is changed.

But the Custom Doctype fields is not reflected. So we used the Translation doctype to change the text to french language.

Now,

Only this text is not converting,

‘Phone Number +225-0556 set in field telephone is not valid.’

Usually when i change the language the exception message from api also return in french only. But for the above exception it is returning in english in both api and erpnext

I can’t use translation doc type for this, because it is case sensitive it seem, even space or caps also is not recognizing. This exception error message also dynamic.

Phone Number {phone_number} set in field {telephone} is not valid.

How to achieve this exception text in french? Thank you in advance

I am using erpnext 15 version.