diff --git a/crates/oidc-client/src/error.rs b/crates/oidc-client/src/error.rs
index 955750b2..cb667c6e 100644
--- a/crates/oidc-client/src/error.rs
+++ b/crates/oidc-client/src/error.rs
@@ -451,9 +451,13 @@ pub enum UserInfoError {
     #[error("could not decoded response content-type: {0}")]
     DecodeResponseContentType(#[from] ToStrError),
 
+    /// The content-type is not valid.
+    #[error("invalid response content-type: {0}")]
+    InvalidResponseContentTypeValue(#[from] mime::FromStrError),
+
     /// The content-type is not the one that was expected.
-    #[error("invalid response content-type {got:?}, expected {expected:?}")]
-    InvalidResponseContentType {
+    #[error("unexpected response content-type {got:?}, expected {expected:?}")]
+    UnexpectedResponseContentType {
         /// The expected content-type.
         expected: String,
         /// The returned content-type.
diff --git a/crates/oidc-client/src/requests/userinfo.rs b/crates/oidc-client/src/requests/userinfo.rs
index c4b8d5e2..89a7698b 100644
--- a/crates/oidc-client/src/requests/userinfo.rs
+++ b/crates/oidc-client/src/requests/userinfo.rs
@@ -23,6 +23,7 @@ use headers::{Authorization, HeaderMapExt, HeaderValue};
 use http::header::{ACCEPT, CONTENT_TYPE};
 use mas_http::CatchHttpCodesLayer;
 use mas_jose::claims;
+use mime::Mime;
 use serde_json::Value;
 use tower::{Layer, Service, ServiceExt};
 use url::Url;
@@ -98,16 +99,17 @@ pub async fn fetch_userinfo(
         .call(userinfo_request)
         .await?;
 
-    let content_type = userinfo_response
+    let content_type: Mime = userinfo_response
         .headers()
         .get(CONTENT_TYPE)
         .ok_or(UserInfoError::MissingResponseContentType)?
-        .to_str()?;
+        .to_str()?
+        .parse()?;
 
-    if content_type != expected_content_type {
-        return Err(UserInfoError::InvalidResponseContentType {
+    if content_type.essence_str() != expected_content_type {
+        return Err(UserInfoError::UnexpectedResponseContentType {
             expected: expected_content_type.to_owned(),
-            got: content_type.to_owned(),
+            got: content_type.to_string(),
         });
     }