Can't get Field "File upload " as " Required

Hello,
​
On a form, I have a field to upload file. This field validation is set to "Required".
But, when I send the form without anything in this field, the form works...
I also use "Google NoCaptcha" on this form.
​
Thank you in advance for your help.

Hi Fredd,
​
Please post a link to the form so we can take a quick look.
​
Bob

Hi Bob,
​
The site is under development.
Here is the link :
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- http://flytrans.bgp-info.com/index.php?option=com_chronoforms5&chronoform=Candidature-spontanee
- Field "Votre CV"

Username : chrono
Password : ch3265
​
Thank you in advance.

Hi Bob,
​
Did you have a little time to look at my problem ?
​
Thank you in advance for your help.
​
Fredd