diff --git a/tracetools_trace/tracetools_trace/tools/lttng.py b/tracetools_trace/tracetools_trace/tools/lttng.py
index 2f0b5eb..2c8dca7 100644
--- a/tracetools_trace/tracetools_trace/tools/lttng.py
+++ b/tracetools_trace/tracetools_trace/tools/lttng.py
@@ -25,7 +25,6 @@ try:
     _lttng = lttng_impl
 except ImportError:
     # Fall back on empty functions
-    print('Warning: lttng Python package not found', file=sys.stderr)
     from . import lttng_stub
 
     _lttng = lttng_stub
diff --git a/tracetools_trace/tracetools_trace/tools/lttng_stub.py b/tracetools_trace/tracetools_trace/tools/lttng_stub.py
index 47c0c63..358ad70 100644
--- a/tracetools_trace/tracetools_trace/tools/lttng_stub.py
+++ b/tracetools_trace/tracetools_trace/tools/lttng_stub.py
@@ -15,17 +15,20 @@
 """Stub version of the interface for tracing with LTTng."""
 
 
+ERROR_MESSAGE = 'lttng Python module not found'
+
+
 def setup(*args, **kwargs) -> None:
-    pass
+    raise RuntimeError(ERROR_MESSAGE)
 
 
 def start(*args, **kwargs) -> None:
-    pass
+    raise RuntimeError(ERROR_MESSAGE)
 
 
 def stop(*args, **kwargs) -> None:
-    pass
+    raise RuntimeError(ERROR_MESSAGE)
 
 
 def destroy(*args, **kwargs) -> None:
-    pass
+    raise RuntimeError(ERROR_MESSAGE)