diff --git a/addons/mail/models/mail_template.py b/addons/mail/models/mail_template.py
index 5e93ebc3544..5e9a96b3959 100644
--- a/addons/mail/models/mail_template.py
+++ b/addons/mail/models/mail_template.py
@@ -63,7 +63,7 @@ def format_amount(env, amount, currency):
     lang = env['res.lang']._lang_get(env.context.get('lang') or 'en_US')
 
     formatted_amount = lang.format(fmt, currency.round(amount), grouping=True, monetary=True)\
-        .replace(r' ', u'\N{NO-BREAK SPACE}').replace(r'-', u'\u2011')
+        .replace(r' ', u'\N{NO-BREAK SPACE}').replace(r'-', u'-\N{ZERO WIDTH NO-BREAK SPACE}')
 
     pre = post = u''
     if currency.position == 'before':