partner-contact/partner_coc/views/res_partner_view.xml

<?xml version="1.0" encoding="UTF-8"?>
<openerp>
<data>
    <!-- Add coc_registration_number to res partner view -->
    <record model="ir.ui.view" id="view_partner_form">
        <field name="name">view.partner.form</field>
        <field name="model">res.partner</field>
        <field name="inherit_id" ref="base.view_partner_form"/>
        <field name="priority" eval="10"/>
        <field name="arch" type="xml">
            <xpath expr="//page[@name='sales_purchases']/group/group/field[@name='lang']" position="after">
                <field name="coc_registration_number" attrs="{'invisible': [('is_company','!=',True)]}"/>
            </xpath>
        </field>
    </record>
</data>
</openerp>