diff --git a/biscuit_test.py b/biscuit_test.py
index 8d49186..e3f6a09 100644
--- a/biscuit_test.py
+++ b/biscuit_test.py
@@ -4,7 +4,7 @@
 
 import pytest
 
-from biscuit_auth import Algorithm, KeyPair, Authorizer, AuthorizerBuilder, Biscuit, BiscuitBuilder, BlockBuilder, Check, Fact, KeyPair, Policy, PrivateKey, PublicKey, Rule, UnverifiedBiscuit
+from biscuit_auth import Algorithm, KeyPair, Authorizer, AuthorizerBuilder, Biscuit, BiscuitBuilder, BlockBuilder, Check, Fact, KeyPair, Policy, PrivateKey, PublicKey, Rule, UnverifiedBiscuit, AuthorizationError
 
 def test_fact():
     fact = Fact('fact(1, true, "", "Test", hex:aabbcc, 2023-04-29T01:00:00Z)')
@@ -237,6 +237,16 @@ def choose_key(kid):
     except:
       pass
 
+def test_authorizer_exception():
+    authorizer = AuthorizerBuilder("check if true; reject if true; allow if false; deny if true;").build_unauthenticated()
+    try:
+        authorizer.authorize()
+        assert False
+    except AuthorizationError as e:
+        (args,) = e.args
+        assert args['matched_policy'] == {'code': 'deny if true', 'policy_id': 1}
+        assert args['checks'] == [{'authorizer_check': True, 'block_id': None, 'check_id': 1, 'code': 'reject if true'}]
+
 def test_complete_lifecycle():
     private_key = PrivateKey("ed25519-private/473b5189232f3f597b5c2f3f9b0d5e28b1ee4e7cce67ec6b7fbf5984157a6b97")
     root = KeyPair.from_private_key(private_key)
@@ -257,7 +267,7 @@ def test_complete_lifecycle():
 
     policy = authorizer.authorize()
 
-    assert policy == 0
+    assert policy == {'code': 'allow if user("1234")', 'policy_id': 0}
 
     rule = Rule("u($id) <- user($id), $id == {id}", { 'id': "1234"})
     facts = authorizer.query(rule)
@@ -290,7 +300,7 @@ def test_snapshot():
 
     policy = parsed.authorize()
 
-    assert policy == 0
+    assert policy == {'code': 'allow if user("1234")', 'policy_id': 0}
 
     rule = Rule("u($id) <- user($id), $id == {id}", { 'id': "1234"})
     facts = parsed.query(rule)
@@ -305,7 +315,7 @@ def test_snapshot():
 
     raw_policy = parsed_from_raw.authorize()
 
-    assert raw_policy == 0
+    assert raw_policy == {'code': 'allow if user("1234")', 'policy_id': 0}
 
     rule = Rule("u($id) <- user($id), $id == {id}", { 'id': "1234"})
     raw_facts = parsed_from_raw.query(rule)
@@ -461,5 +471,4 @@ def test(left, right):
       'other': lambda x : x == 2,
     })
     policy = authorizer.build_unauthenticated().authorize()
-    assert policy == 0
-
+    assert policy == {'code': 'allow if 1.extern::test(1)', 'policy_id': 0}
diff --git a/docs/basic-use.rst b/docs/basic-use.rst
index abeda7f..130a301 100644
--- a/docs/basic-use.rst
+++ b/docs/basic-use.rst
@@ -74,7 +74,7 @@ Parse and authorize a biscuit token
 >>> token = Biscuit.from_base64("En0KEwoEMTIzNBgDIgkKBwgKEgMYgAgSJAgAEiCp8D9laR_CXmFmiUlo6zi8L63iapXDxX1evELp4HVaBRpAx3Mkwu2f2AcNq48IZwu-pxACq1stL76DSMGEugmiduuTVwMqLmgKZ4VFgzeydCrYY_Id3MkxgTgjXzEHUH4DDSIiCiB55I7ykL9wQXHRDqUnSgZwCdYNdO7c8LZEj0VH5sy3-Q==", public_key)
 >>> authorizer = AuthorizerBuilder( """ time({now}); allow if user($u); """, { 'now': datetime.now(tz = timezone.utc)} ).build(token)
 >>> authorizer.authorize()
-0
+{'policy_id': 0, 'code': 'allow if user($u)'}
 
 In order to help with key rotation, biscuit tokens can optionally carry a root key identifier, helping the verifying party choose between several valid public keys.
 
@@ -88,7 +88,7 @@ In order to help with key rotation, biscuit tokens can optionally carry a root k
 >>> token = Biscuit.from_base64("CAESfQoTCgQxMjM0GAMiCQoHCAoSAxiACBIkCAASII5WVsvM52T91C12wnzButmyzmtGSX_rbM6hCSIJihX2GkDwAcVxTnY8aeMLm-i2R_VzTfIMQZya49ogXO2h2Fg2TJsDcG3udIki9il5PA05lKUwrfPNroS7Qg5e04AyLLcHIiIKII5rh75jrCrgE6Rzw6GVYczMn1IOo287uO4Ef5wp7obY", public_key_fn)
 >>> authorizer = AuthorizerBuilder( """ time({now}); allow if user($u); """, { 'now': datetime.now(tz = timezone.utc)} ).build(token)
 >>> authorizer.authorize()
-0
+{'policy_id': 0, 'code': 'allow if user($u)'}
 
 It is possible to parse a biscuit token without verifying its signatures,for instance to inspect its contents, extract revocation ids or append a block.
 
diff --git a/src/lib.rs b/src/lib.rs
index cf049dd..cb33d3c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -9,6 +9,7 @@
 #![allow(clippy::useless_conversion)]
 use ::biscuit_auth::builder::MapKey;
 use ::biscuit_auth::datalog::ExternFunc;
+use ::biscuit_auth::error::MatchedPolicy;
 use ::biscuit_auth::AuthorizerBuilder;
 use ::biscuit_auth::RootKeyProvider;
 use ::biscuit_auth::UnverifiedBiscuit;
@@ -38,6 +39,27 @@ create_exception!(
     AuthorizationError,
     pyo3::exceptions::PyException
 );
+
+#[derive(IntoPyObject)]
+struct AuthorizationErrorData {
+    matched_policy: Option<MatchedPolicyData>,
+    checks: Vec<FailedCheckData>,
+}
+
+#[derive(IntoPyObject)]
+pub struct MatchedPolicyData {
+    policy_id: usize,
+    code: String,
+}
+
+#[derive(IntoPyObject)]
+struct FailedCheckData {
+    authorizer_check: bool,
+    block_id: Option<u32>,
+    check_id: u32,
+    code: String,
+}
+
 create_exception!(
     biscuit_auth,
     BiscuitBuildError,
@@ -785,10 +807,44 @@ impl PyAuthorizer {
     ///
     /// :return: the index of the matched allow rule
     /// :rtype: int
-    pub fn authorize(&mut self) -> PyResult<usize> {
-        self.0
-            .authorize()
-            .map_err(|error| AuthorizationError::new_err(error.to_string()))
+    pub fn authorize(&mut self) -> PyResult<MatchedPolicyData> {
+        let all_policies = self.0.dump().3;
+        let policy_id = self.0.authorize().map_err(|error| match error {
+            error::Token::FailedLogic(error::Logic::Unauthorized {
+                policy: MatchedPolicy::Deny(pid),
+                checks,
+            }) => AuthorizationError::new_err(AuthorizationErrorData {
+                matched_policy: Some(MatchedPolicyData {
+                    policy_id: pid,
+                    code: all_policies.get(pid).unwrap().to_string(),
+                }),
+                checks: checks
+                    .into_iter()
+                    .map(|c| match c {
+                        error::FailedCheck::Block(failed_block_check) => FailedCheckData {
+                            authorizer_check: false,
+                            block_id: Some(failed_block_check.block_id),
+                            check_id: failed_block_check.check_id,
+                            code: failed_block_check.rule,
+                        },
+                        error::FailedCheck::Authorizer(failed_authorizer_check) => {
+                            FailedCheckData {
+                                authorizer_check: true,
+                                block_id: None,
+                                check_id: failed_authorizer_check.check_id,
+                                code: failed_authorizer_check.rule,
+                            }
+                        }
+                    })
+                    .collect(),
+            }),
+            _ => AuthorizationError::new_err(error.to_string()),
+        })?;
+
+        Ok(MatchedPolicyData {
+            policy_id,
+            code: all_policies.get(policy_id).unwrap().to_string(),
+        })
     }
 
     /// Query the authorizer by returning all the `Fact`s generated by the provided `Rule`. The generated facts won't be