diff --git a/corporate/lib/stripe.py b/corporate/lib/stripe.py
index 8a0b356513..42214d8ed2 100644
--- a/corporate/lib/stripe.py
+++ b/corporate/lib/stripe.py
@@ -656,8 +656,8 @@ def do_change_remote_server_plan_type(remote_server: RemoteZulipServer, plan_typ
 def do_deactivate_remote_server(remote_server: RemoteZulipServer) -> None:
     if remote_server.deactivated:
         billing_logger.warning(
-            f"Cannot deactivate remote server with ID {remote_server.id}, "
-            "server has already been deactivated."
+            "Cannot deactivate remote server with ID %d, server has already been deactivated.",
+            remote_server.id,
         )
         return
 
diff --git a/zerver/lib/queue.py b/zerver/lib/queue.py
index 3278ee92e0..44975fad1b 100644
--- a/zerver/lib/queue.py
+++ b/zerver/lib/queue.py
@@ -88,7 +88,7 @@ class QueueClient(Generic[ChannelT], metaclass=ABCMeta):
         return f"{queue_name}_{str(random.getrandbits(16))}"
 
     def _reconnect_consumer_callback(self, queue: str, consumer: Consumer[ChannelT]) -> None:
-        self.log.info(f"Queue reconnecting saved consumer {consumer} to queue {queue}")
+        self.log.info("Queue reconnecting saved consumer %r to queue %s", consumer, queue)
         self.ensure_queue(
             queue,
             lambda channel: channel.basic_consume(
@@ -142,7 +142,7 @@ class SimpleQueueClient(QueueClient[BlockingChannel]):
         start = time.time()
         self.connection = pika.BlockingConnection(self._get_parameters())
         self.channel = self.connection.channel()
-        self.log.info(f"SimpleQueueClient connected (connecting took {time.time() - start:.3f}s)")
+        self.log.info("SimpleQueueClient connected (connecting took %.3fs)", time.time() - start)
 
     def _reconnect(self) -> None:
         self.connection = None
diff --git a/zproject/backends.py b/zproject/backends.py
index 50eaa9e9c8..0a1d31ce5d 100644
--- a/zproject/backends.py
+++ b/zproject/backends.py
@@ -2299,8 +2299,8 @@ class SAMLAuthBackend(SocialAuthMixin, SAMLAuth):
             if idps_without_limit_to_subdomains:
                 self.logger.error(
                     "SAML_REQUIRE_LIMIT_TO_SUBDOMAINS is enabled and the following IdPs don't have"
-                    " limit_to_subdomains specified and will be ignored:"
-                    f" {idps_without_limit_to_subdomains}"
+                    " limit_to_subdomains specified and will be ignored: %r",
+                    idps_without_limit_to_subdomains,
                 )
                 for idp_name in idps_without_limit_to_subdomains:
                     del settings.SOCIAL_AUTH_SAML_ENABLED_IDPS[idp_name]