product_template.xml

the view to add the customizing field to the product module

<?xml version="1.0" encoding="utf-8"?><odoo><data><record id="product_template_only_form_view_inherit" model="ir.ui.view"><field name="name">product.template.common.form</field><field name="model">product.template</field><field name="inherit_id" ref="product.product_template_only_form_view " /><field name="arch" type="xml"><xpath expr="//field[@name='list_price']" position="after"><field name="list_price"/></xpath></field></record></data></odoo>

models file python

product_template.py

-- coding: utf-8 --

from odoo import models, fields , api

from odoo.addons import decimal_precision as dp

from odoo.exceptions import ValidationError, RedirectWarning, except_orm

from odoo.tools import pycompat

class ProductTemplate(models.Model):

_inherit = 'product.template'

_name = 'product.template'_columns={'remise': fields.float('remise du fournisseur', size=10, required=True),'marge': fields.float('marge', size=10, required=True),'total_reste': fields.float('Reste', size=10, required=True),}remise = fields.float('remise du fournisseur', size=10, required=True)

You are putting the same field list_price after list_price, you should replace the field that is inside the xpath by the field you want.

<record id="product_template_only_form_view_inherit" model="ir.ui.view"><field name="name">product.template.common.form</field><field name="model">product.template</field><field name="inherit_id" ref="product.product_template_only_form_view " /><field name="arch" type="xml"><xpath expr="//field[@name='list_price']" position="after"><field name="your_custom_field"/></xpath></field></record>