Hi deep, i have created a filter like the following: and agenda_emp_liee is a 'agenda_emp_liee': fields.function(itk_facturation_fct_get_employee_liee,type='many2many',string=U'Employé lié',store=False,relation="hr.employee"), but it dosen't work

When you say filter, did you mean the filter in the Search bar? Deep actually said the opposite, you need to have the function stored in the database to be used in the a search. Also, the field need to be included in the view (although it can be invisible).

You also might want to check the answer to this question: https://www.odoo.com/forum/help-1/question/how-can-i-use-a-field-function-in-the-domain-filter-137

@John Doe, Yup I too meant the same, Stored functional field can be used in domain filter..... typo error :)