diff --git a/lib/id_tracker.cc b/lib/id_tracker.cc
index c428e4f..490828d 100644
--- a/lib/id_tracker.cc
+++ b/lib/id_tracker.cc
@@ -302,7 +302,7 @@ void init_id_tracker(pybind11::module &m)
              py::arg("fname"), py::arg("relation_depth") = 0)
         .def("complete_backward_references",
              [](IdTracker &self, std::filesystem::path const &fname, int relation_depth) {
-                self.complete_backward_references(osmium::io::File{fname}, relation_depth);
+                self.complete_backward_references(osmium::io::File{fname.string()}, relation_depth);
              },
              py::arg("fname"), py::arg("relation_depth") = 0)
         .def("complete_forward_references", &IdTracker::complete_forward_references,
@@ -314,7 +314,7 @@ void init_id_tracker(pybind11::module &m)
              py::arg("fname"), py::arg("relation_depth") = 0)
         .def("complete_forward_references",
              [](IdTracker &self, std::filesystem::path const &fname, int relation_depth) {
-                self.complete_forward_references(osmium::io::File{fname.c_str()}, relation_depth);
+                self.complete_forward_references(osmium::io::File{fname.string()}, relation_depth);
              },
              py::arg("fname"), py::arg("relation_depth") = 0)
         .def("id_filter",
diff --git a/lib/io.cc b/lib/io.cc
index 0eeff1a..5b4a545 100644
--- a/lib/io.cc
+++ b/lib/io.cc
@@ -31,10 +31,10 @@ PYBIND11_MODULE(io, m)
         .def(py::init<std::string>())
         .def(py::init<std::string, std::string>())
         .def(py::init<>([] (std::filesystem::path const &file) {
-                 return new osmium::io::File(file.c_str());
+                 return new osmium::io::File(file.string());
              }))
         .def(py::init<>([] (std::filesystem::path const &file, const char *format) {
-                 return new osmium::io::File(file.c_str(), format);
+                 return new osmium::io::File(file.string(), format);
              }))
         .def_property("has_multiple_object_versions",
                       &osmium::io::File::has_multiple_object_versions,
@@ -78,10 +78,10 @@ PYBIND11_MODULE(io, m)
         .def(py::init<std::string>())
         .def(py::init<std::string, osmium::osm_entity_bits::type>())
         .def(py::init<>([] (std::filesystem::path const &file) {
-                 return new osmium::io::Reader(file.c_str());
+                 return new osmium::io::Reader(file.string());
              }))
         .def(py::init<>([] (std::filesystem::path const &file, osmium::osm_entity_bits::type etype) {
-                 return new osmium::io::Reader(file.c_str(), etype);
+                 return new osmium::io::Reader(file.string(), etype);
              }))
         .def(py::init<osmium::io::File>(),
              py::keep_alive<1, 2>())
@@ -97,7 +97,7 @@ PYBIND11_MODULE(io, m)
     py::class_<osmium::io::Writer>(m, "Writer")
         .def(py::init<std::string>())
         .def(py::init<>([] (std::filesystem::path const &file) {
-                 return new osmium::io::Writer(file.c_str());
+                 return new osmium::io::Writer(file.string());
              }))
         .def(py::init<osmium::io::File>())
         .def(py::init<std::string, osmium::io::Header>())
diff --git a/lib/osmium.cc b/lib/osmium.cc
index 72cce25..1d7c0cf 100644
--- a/lib/osmium.cc
+++ b/lib/osmium.cc
@@ -106,14 +106,14 @@ PYBIND11_MODULE(_osmium, m) {
           py::arg("filename"));
     m.def("apply", [](std::filesystem::path const &fn, pyosmium::BaseHandler &h)
                    {
-                       osmium::io::Reader rd{fn};
+                       osmium::io::Reader rd{fn.string()};
                        pyosmium::apply(rd, h);
                    },
           py::arg("filename"), py::arg("handler"));
     m.def("apply", [](std::filesystem::path const &fn, py::args args)
                      {
                          pyosmium::HandlerChain handler{args};
-                         osmium::io::Reader rd{fn};
+                         osmium::io::Reader rd{fn.string()};
                          pyosmium::apply(rd, handler);
                      },
           py::arg("filename"));
diff --git a/lib/simple_writer.cc b/lib/simple_writer.cc
index 80b3d84..5126c77 100644
--- a/lib/simple_writer.cc
+++ b/lib/simple_writer.cc
@@ -358,7 +358,7 @@ void init_simple_writer(pybind11::module &m)
              py::arg("filetype") = "")
         .def(py::init<>([] (std::filesystem::path const &file, unsigned long bufsz,
                             osmium::io::Header const *header, bool overwrite) {
-                 return new SimpleWriter(file.c_str(), bufsz, header, overwrite, "");
+                 return new SimpleWriter(file.string().c_str(), bufsz, header, overwrite, "");
              }),
              py::arg("filename"), py::arg("bufsz") = 4096*1024,
              py::arg("header") = nullptr,
diff --git a/test/test_file_processor.py b/test/test_file_processor.py
index 8d3a50e..c3d90ab 100644
--- a/test/test_file_processor.py
+++ b/test/test_file_processor.py
@@ -241,7 +241,7 @@ def test_filtered_handler_basehandler(opl_buffer, tmp_path):
 
     ids = IDCollector()
 
-    o.apply(str(testf), ids)
+    o.apply(testf, ids)
 
     assert ids.nodes == [3]
     assert ids.ways == [2]