formatLang(object.amount_total, currency_obj=currency_object)

I believe you can get currency_object (EURO) from some field in the object, usually from company_id.

-- begin edited answer --

I'm forget to fact that object email template can't access report service. So, pass it to the template. In the model related to the email template define a method, something like this.

def parser(self, cr, uid, ids, context=None):

        report_service = 'dummy_report'

        service = netsvc.LocalService(report_service)
        parser = service.parser(cr, uid, service.name2, context)
        pool = self.pool.get('your.model')
        obj = pool.browse(cr, uid, ids, context) # relative to your model
        parser.set_context(obj, {'model': u'your.model'}, 'pdf') # whatever report type will suffice

        return parser

Then call it in your email template. Now the parser can access formatLang. Furhermore you can access all data to build that report.

I think this method is a little bit aggresive, I hope you can get the idea. I'm willing to see any improvement or new method :D

I am looking for a solution for that, too. Did anybody succeed in solving the problem by Ben Bernard's advice?

Hi!

In your mail.template, replace with t-esc="'%.2f' % (object.amount)"

Because I also encountered this issue, here's a easier work-around :

In your mail.template, replace ${object.amount_total} with ${"%.2f" | format(object.amount_total)}

Enjoy !