partner-contact/partner_sector/views/res_partner_view.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- © 2015 Antiun Ingenieria S.L. - Javier Iniesta
     License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html). -->
<openerp>
<data>

<record model="ir.ui.view" id="view_partner_form_sector">
    <field name="name">Partner form with sector</field>
    <field name="model">res.partner</field>
    <field name="inherit_id" ref="base.view_partner_form"/>
    <field name="arch" type="xml">
        <field name="phone" position="before">
            <field name="sector_id" placeholder="Sector"
                   options='{"no_open": True}'
                   attrs="{'invisible': [('is_company', '=', False)]}"/>
            <field name="secondary_sector_ids" widget="many2many_tags"
                   attrs="{'invisible': [('is_company', '=', False)]}"/>
        </field>
    </field>
</record>

<record model="ir.ui.view" id="view_partner_tree_sector">
    <field name="name">Partner tree with sector</field>
    <field name="model">res.partner</field>
    <field name="inherit_id" ref="base.view_partner_tree"/>
    <field name="arch" type="xml">
        <field name="email" position="after">
            <field name="sector_id"
                   attrs="{'invisible': [('is_company', '=', False)]}"/>
        </field>
    </field>
</record>

<record model="ir.ui.view" id="view_res_partner_filter_sector">
    <field name="name">Partner search with sector</field>
    <field name="model">res.partner</field>
    <field name="inherit_id" ref="base.view_res_partner_filter"/>
    <field name="arch" type="xml">
        <field name="category_id" position="after">
            <field name="sector_id"
                   string="Sector"
                   filter_domain="['|',('sector_id','ilike',self),
                                       ('secondary_sector_ids','ilike',self)]"/>
        </field>
        <filter string="Salesperson" position="after">
            <filter string="Sector"
                    domain="[('is_company','=', True)]"
                    context="{'group_by': 'sector_id'}"/>
        </filter>
    </field>
</record>

</data>
</openerp>