diff --git a/facho/fe/form.py b/facho/fe/form.py
index fba0c4d..79f7188 100644
--- a/facho/fe/form.py
+++ b/facho/fe/form.py
@@ -55,6 +55,10 @@ class AmountCollection(Collection):
 class Amount:
     def __init__(self, amount: int or float or Amount, currency: Currency = Currency('COP')):
 
+        #DIAN 1.7.-2020: 1.2.3.1
+        if amount < 0:
+            raise ValueError('amount must be positive >= 0')
+        
         if isinstance(amount, Amount):
             self.amount = amount.amount
             self.currency = amount.currency
diff --git a/tests/test_amount.py b/tests/test_amount.py
index 04bf846..76a0d8c 100644
--- a/tests/test_amount.py
+++ b/tests/test_amount.py
@@ -10,6 +10,10 @@ import pytest
 import facho.fe.form as form
 
 
+def test_amount_positive():
+    with pytest.raises(ValueError):
+        form.Amount(-1.0)
+
 def test_amount_equals():
     price1 = form.Amount(110.0)
     price2 = form.Amount(100 + 10.0)