diff --git a/src/pyswip/easy.py b/src/pyswip/easy.py
index 6acbfe8..a1470ae 100644
--- a/src/pyswip/easy.py
+++ b/src/pyswip/easy.py
@@ -106,7 +106,7 @@
 class InvalidTypeError(TypeError):
     def __init__(self, *args):
         type_ = args and args[0] or "Unknown"
-        msg = "Term is expected to be of type: '%s'" % type_
+        msg = f"Term is expected to be of type: '{type_}'"
         Exception.__init__(self, msg, *args)
 
 
@@ -116,7 +116,7 @@ class ArgumentTypeError(Exception):
     """
 
     def __init__(self, expected, got):
-        msg = "Expected an argument of type '%s' but got '%s'" % (expected, got)
+        msg = f"Expected an argument of type '{expected}' but got '{got}'"
         Exception.__init__(self, msg)
 
 
@@ -290,7 +290,7 @@ def __str__(self):
             return self.__repr__()
 
     def __repr__(self):
-        return "Variable(%s)" % self.handle
+        return f"Variable({self.handle})"
 
     def put(self, term):
         # PL_put_variable(term)
@@ -703,7 +703,7 @@ class Query(object):
     def __init__(self, *terms, **kwargs):
         for key in kwargs:
             if key not in ["flags", "module"]:
-                raise Exception("Invalid kwarg: %s" % key, key)
+                raise Exception(f"Invalid kwarg: {key}", key)
 
         flags = kwargs.get("flags", PL_Q_NODEBUG | PL_Q_CATCH_EXCEPTION)
         module = kwargs.get("module", None)
diff --git a/src/pyswip/examples/coins.py b/src/pyswip/examples/coins.py
index 995f73e..79b9346 100644
--- a/src/pyswip/examples/coins.py
+++ b/src/pyswip/examples/coins.py
@@ -38,14 +38,14 @@ def solve(
     """
     Solves the coins problem.
 
-    Finds and returns combinations of ``coin_count`` coins that makes ``total``cents.
+    Finds and returns combinations of ``coin_count`` coins that makes ``total`` cents.
 
     :param coin_count: Number of coins
     :param total_cents: Total cent value of coins
     """
     cents = [1, 5, 10, 50, 100]
     query = Prolog.query(
-        "coins(%s, %s, Solution)", coin_count, total_cents, maxresult=max_solutions
+        "coins(%p, %p, Solution)", coin_count, total_cents, maxresult=max_solutions
     )
     return [
         {cent: count for cent, count in zip(cents, soln["Solution"])} for soln in query
diff --git a/src/pyswip/examples/hanoi.py b/src/pyswip/examples/hanoi.py
index 1b03924..707476b 100644
--- a/src/pyswip/examples/hanoi.py
+++ b/src/pyswip/examples/hanoi.py
@@ -117,7 +117,7 @@ def solve(disk_count: int = 3, simple: bool = False, file: IO = None) -> None:
         tower = Tower(disk_count, file=file)
         notifier = Notifier(tower.move)
         Prolog.register_foreign(notifier.notify)
-    list(Prolog.query("hanoi(%s)", disk_count))
+    list(Prolog.query("hanoi(%p)", disk_count))
 
 
 def prolog_source() -> str:
diff --git a/src/pyswip/prolog.py b/src/pyswip/prolog.py
index fdaf6e1..43a001a 100644
--- a/src/pyswip/prolog.py
+++ b/src/pyswip/prolog.py
@@ -64,7 +64,7 @@
 __all__ = "PrologError", "NestedQueryError", "Prolog"
 
 
-RE_PLACEHOLDER = re.compile(r"%s")
+RE_PLACEHOLDER = re.compile(r"%p")
 
 
 class PrologError(Exception):
@@ -86,7 +86,7 @@ def __initialize():
     args.append("-q")  # --quiet
     args.append("--nosignals")  # "Inhibit any signal handling by Prolog"
     if SWI_HOME_DIR:
-        args.append("--home=%s" % SWI_HOME_DIR)
+        args.append(f"--home={SWI_HOME_DIR}")
 
     result = PL_initialise(len(args), args)
     # result is a boolean variable (i.e. 0 or 1) indicating whether the
@@ -207,7 +207,7 @@ def asserta(cls, format: str, *args, catcherrors: bool = False) -> None:
 
         :param format:
             The format to be used to generate the clause.
-            The placeholders (``%s``) are replaced by the ``args`` if one ore more arguments are given.
+            The placeholders (``%p``) are replaced by the ``args`` if one ore more arguments are given.
         :param args:
             Arguments to replace the placeholders in the ``format`` string
         :param catcherrors:
@@ -224,7 +224,7 @@ def asserta(cls, format: str, *args, catcherrors: bool = False) -> None:
         ...    big(A),
         ...    small(B)''')
         >>> nums = list(range(5))
-        >>> Prolog.asserta("numbers(%s)", nums)
+        >>> Prolog.asserta("numbers(%p)", nums)
         """
         next(
             cls.query(format.join(["asserta((", "))."]), *args, catcherrors=catcherrors)
@@ -241,7 +241,7 @@ def assertz(cls, format: str, *args, catcherrors: bool = False) -> None:
 
         :param format:
             The format to be used to generate the clause.
-            The placeholders (``%s``) are replaced by the ``args`` if one ore more arguments are given.
+            The placeholders (``%p``) are replaced by the ``args`` if one ore more arguments are given.
         :param catcherrors:
             Catches the exception raised during goal execution
 
@@ -256,7 +256,7 @@ def assertz(cls, format: str, *args, catcherrors: bool = False) -> None:
         ...    big(A),
         ...    small(B)''')
         >>> nums = list(range(5))
-        >>> Prolog.assertz("numbers(%s)", nums)
+        >>> Prolog.assertz("numbers(%p)", nums)
         """
         next(
             cls.query(format.join(["assertz((", "))."]), *args, catcherrors=catcherrors)
@@ -295,7 +295,7 @@ def retract(cls, format: str, *args, catcherrors: bool = False) -> None:
 
         :param format:
             The format to be used to generate the term.
-            The placeholders (``%s``) are replaced by the ``args`` if one ore more arguments are given.
+            The placeholders (``%p``) are replaced by the ``args`` if one ore more arguments are given.
         :param catcherrors:
             Catches the exception raised during goal execution
 
@@ -315,10 +315,10 @@ def retract(cls, format: str, *args, catcherrors: bool = False) -> None:
         >>> Prolog.dynamic("numbers/1")
         >>> nums = list(range(5))
         >>> Prolog.asserta("numbers(10)")
-        >>> Prolog.asserta("numbers(%s)", nums)
+        >>> Prolog.asserta("numbers(%p)", nums)
         >>> list(Prolog.query("numbers(X)"))
         [{'X': [0, 1, 2, 3, 4]}, {'X': 10}]
-        >>> Prolog.retract("numbers(%s)", nums)
+        >>> Prolog.retract("numbers(%p)", nums)
         >>> list(Prolog.query("numbers(X)"))
         [{'X': 10}]
         """
@@ -408,7 +408,7 @@ def query(
 
         :param format:
             The format to be used to generate the query.
-            The placeholders (``%s``) are replaced by the ``args`` if one ore more arguments are given.
+            The placeholders (``%p``) are replaced by the ``args`` if one ore more arguments are given.
         :param args:
             Arguments to replace the placeholders in the ``format`` string
         :param maxresult:
diff --git a/tests/test_prolog.py b/tests/test_prolog.py
index 80ebf1d..f32ea0f 100644
--- a/tests/test_prolog.py
+++ b/tests/test_prolog.py
@@ -128,13 +128,13 @@ def test_retract(self):
 format_prolog_fixture = [
     ("", (), ""),
     ("no-args", (), "no-args"),
-    ("before%safter", ("text",), 'before"text"after'),
-    ("before%safter", (123,), "before123after"),
-    ("before%safter", (123.45,), "before123.45after"),
-    ("before%safter", (Atom("foo"),), "before'foo'after"),
-    ("before%safter", (Variable(name="Foo"),), "beforeFooafter"),
+    ("before%pafter", ("text",), 'before"text"after'),
+    ("before%pafter", (123,), "before123after"),
+    ("before%pafter", (123.45,), "before123.45after"),
+    ("before%pafter", (Atom("foo"),), "before'foo'after"),
+    ("before%pafter", (Variable(name="Foo"),), "beforeFooafter"),
     (
-        "before%safter",
+        "before%pafter",
         (["foo", 38, 45.897, [1, 2, 3]],),
         'before["foo",38,45.897,[1,2,3]]after',
     ),