Custom table_name for table users with devise

Hi
for my app, I have several tables for users (franceusers, belgiumusers,
…) and I would like to use one or another depending on domain
I tried with table_name_prefix and table_name but it seems to not work

class User < ActiveRecord::Base
rolify

Include default devise modules. Others available are:

:token_authenticatable, :confirmable,

:lockable, :timeoutable and :omniauthable

devise :database_authenticatable, :registerable, #:confirmable,
:recoverable, :rememberable, :trackable, :validatable

def self.table_name
debugger
‘franceusers’
end

def self.table_name_prefix
debugger
‘france’
end

thanks to debugger, I can see that is called but not
self.table_name_prefix. And even if self.table_name if called, devise
search users in tables users instead of franceusers

in console
User.table_name => “franceusers”
User.table_name_prefix => “france”

more weird, im also using activeadmin, and when I browse users list, I
have
an error :

Mysql2::Error: Unknown column ‘franceusers.id’ in ‘order clause’: SELECT
users.* FROM users ORDER BY franceusers.id desc LIMIT 30 OFFSET
0

it seems it can find table_prefix for field but not for FROM.

do I do anything bad ? is there another way to change users table name ?

thanks

merci