Hi,

Try this code

<record model="ir.ui.view" id="partenariat_form"> 
<field name="name">partenariat.form</field> 
<field name="model">partenariat</field> 
<field name="type">form</field> 
<field name="arch" type="xml">
 <form string="Formulaire partenariat" version="7.0" > 
        <sheet>
           <group string="Gestion des Partenariats">
                <field name="sujet"/> 
                <field name="organisateur"/>
                <field name="lieu"/> 
                <field name="date_debut"/>
                <field name="date_fin" /> 
            </group>
        </sheet>
    </form>
</field>

</record>

<record model="ir.ui.view" id="salon_form"> 
    <field name="name">salon.form</field> 
    <field name="model">salon</field> 
    <field name="type">form</field> 
    <field name="inherit_id" ref="your_module_name.partenariat_form"/>  
    <field name="arch" type="xml">

            <xpath expr="/form/sheet/group/field[@name='date_fin']" position="after">
                <field name="prix_par_metre_salon" widget="integer"/>
                <field name="espace_reserve_salon" widget="integer"/> 
                <field name="cout_total_salon" widget="integer"/>
            </xpath>  

    </field> 
</record>

i want that the view salon be like the result of this but with inhetance:

<form string="Formulaire Salon" version="7.0" > 
        <sheet>
           <group string="group_test">
               <group string="Gestion des Salons">
                    <field name="sujet"/> 
                    <field name="organisateur"/>
                    <field name="lieu"/> 
                    <field name="date_debut"/>
                    <field name="date_fin" />
                     <field name="prix_par_metre_salon" widget="integer"/>
                    <field name="espace_reserve_salon" widget="integer"/> 
                    <field name="cout_total_salon" widget="integer"/>
                </group>
            </group>
        </sheet>
    </form>