diff --git a/c++/g2_parameters.hpp b/c++/g2_parameters.hpp
index 82216ea..d911df2 100644
--- a/c++/g2_parameters.hpp
+++ b/c++/g2_parameters.hpp
@@ -29,8 +29,8 @@ namespace pomerol2triqs {
     /// indices of operators in TRIQS convention: (block_name, inner_index)
     indices_t index1, index2, index3, index4;
 
-    g2_iw_inu_inup_params_t() {}
-    g2_iw_inu_inup_params_t(gf_struct_t const &gf_struct, double beta) : gf_struct(gf_struct), beta(beta) {}
+    // g2_iw_inu_inup_params_t() {}
+    // g2_iw_inu_inup_params_t(gf_struct_t const &gf_struct, double beta) : gf_struct(gf_struct), beta(beta) {}
   };
 
   struct g2_three_freqs_params_t {
@@ -50,8 +50,8 @@ namespace pomerol2triqs {
     /// indices of operators in TRIQS convention: (block_name, inner_index)
     indices_t index1, index2, index3, index4;
 
-    g2_three_freqs_params_t() {}
-    g2_three_freqs_params_t(gf_struct_t const &gf_struct, double beta) : gf_struct(gf_struct), beta(beta) {}
+    // g2_three_freqs_params_t() {}
+    // g2_three_freqs_params_t(gf_struct_t const &gf_struct, double beta) : gf_struct(gf_struct), beta(beta) {}
   };
 
 /*
diff --git a/c++/pomerol_ed.hpp b/c++/pomerol_ed.hpp
index cd58066..4213915 100644
--- a/c++/pomerol_ed.hpp
+++ b/c++/pomerol_ed.hpp
@@ -119,10 +119,11 @@ namespace pomerol2triqs {
     /// Retarded Green's function on real energy axis
     block_gf<refreq> G_w(gf_struct_t const &gf_struct, double beta, std::pair<double, double> const &energy_window, int n_w, double im_shift = 0);
 
-    /// Two-particle Green's function, Matsubara frequencies
+    /// Two-particle Green's function. Specify frequency cutoff, n_b and n_f.
     TRIQS_WRAP_ARG_AS_DICT
     g2_t G2_iw(g2_iw_inu_inup_params_t const &p);
 
+    /// Two-particle Green's function. Specify three frequencies (wb, wf1, wf2).
     TRIQS_WRAP_ARG_AS_DICT
     g2_three_freqs_t G2_iw_three_freqs(g2_three_freqs_params_t const &p);
 
diff --git a/python/pomerol2triqs_converters.hxx b/python/pomerol2triqs_converters.hxx
index c8eae7d..b20165f 100644
--- a/python/pomerol2triqs_converters.hxx
+++ b/python/pomerol2triqs_converters.hxx
@@ -111,4 +111,112 @@ template <> struct py_converter<g2_iw_inu_inup_params_t> {
  }
 };
 
+}}
+
+
+// --- C++ Python converter for g2_three_freqs_params_t
+#include <triqs/python_tools/converters/vector.hpp>
+#include <triqs/python_tools/converters/string.hpp>
+#include <algorithm>
+
+namespace triqs { namespace py_tools {
+
+template <> struct py_converter<g2_three_freqs_params_t> {
+ static PyObject *c2py(g2_three_freqs_params_t const & x) {
+  PyObject * d = PyDict_New();
+  PyDict_SetItemString( d, "gf_struct"  , convert_to_python(x.gf_struct));
+  PyDict_SetItemString( d, "beta"       , convert_to_python(x.beta));
+  PyDict_SetItemString( d, "channel"    , convert_to_python(x.channel));
+  PyDict_SetItemString( d, "three_freqs", convert_to_python(x.three_freqs));
+  PyDict_SetItemString( d, "index1"     , convert_to_python(x.index1));
+  PyDict_SetItemString( d, "index2"     , convert_to_python(x.index2));
+  PyDict_SetItemString( d, "index3"     , convert_to_python(x.index3));
+  PyDict_SetItemString( d, "index4"     , convert_to_python(x.index4));
+  return d;
+ }
+
+ template <typename T, typename U> static void _get_optional(PyObject *dic, const char *name, T &r, U const &init_default) {
+  if (PyDict_Contains(dic, pyref::string(name)))
+   r = convert_from_python<T>(PyDict_GetItemString(dic, name));
+  else
+   r = init_default;
+ }
+
+ template <typename T> static void _get_optional(PyObject *dic, const char *name, T &r) {
+  if (PyDict_Contains(dic, pyref::string(name)))
+   r = convert_from_python<T>(PyDict_GetItemString(dic, name));
+  else
+   r = T{};
+ }
+
+ static g2_three_freqs_params_t py2c(PyObject *dic) {
+  g2_three_freqs_params_t res;
+  res.gf_struct = convert_from_python<gf_struct_t>(PyDict_GetItemString(dic, "gf_struct"));
+  res.beta = convert_from_python<double>(PyDict_GetItemString(dic, "beta"));
+  _get_optional(dic, "channel"    , res.channel       ,PH);
+  res.three_freqs = convert_from_python<three_freqs_t>(PyDict_GetItemString(dic, "three_freqs"));
+  res.index1 = convert_from_python<indices_t>(PyDict_GetItemString(dic, "index1"));
+  res.index2 = convert_from_python<indices_t>(PyDict_GetItemString(dic, "index2"));
+  res.index3 = convert_from_python<indices_t>(PyDict_GetItemString(dic, "index3"));
+  res.index4 = convert_from_python<indices_t>(PyDict_GetItemString(dic, "index4"));
+  return res;
+ }
+
+ template <typename T>
+ static void _check(PyObject *dic, std::stringstream &fs, int &err, const char *name, const char *tname) {
+  if (!convertible_from_python<T>(PyDict_GetItemString(dic, name), false))
+   fs << "\n" << ++err << " The parameter " << name << " does not have the right type : expecting " << tname
+      << " in C++, but got '" << PyDict_GetItemString(dic, name)->ob_type->tp_name << "' in Python.";
+ }
+
+ template <typename T>
+ static void _check_mandatory(PyObject *dic, std::stringstream &fs, int &err, const char *name, const char *tname) {
+  if (!PyDict_Contains(dic, pyref::string(name)))
+   fs << "\n" << ++err << " Mandatory parameter " << name << " is missing.";
+  else _check<T>(dic,fs,err,name,tname);
+ }
+
+ template <typename T>
+ static void _check_optional(PyObject *dic, std::stringstream &fs, int &err, const char *name, const char *tname) {
+  if (PyDict_Contains(dic, pyref::string(name))) _check<T>(dic, fs, err, name, tname);
+ }
+
+ static bool is_convertible(PyObject *dic, bool raise_exception) {
+  if (dic == nullptr or !PyDict_Check(dic)) {
+   if (raise_exception) { PyErr_SetString(PyExc_TypeError, "The function must be called with named arguments");}
+   return false;
+  }
+  std::stringstream fs, fs2; int err=0;
+
+#ifndef TRIQS_ALLOW_UNUSED_PARAMETERS
+  std::vector<std::string> ks, all_keys = {"gf_struct","beta","channel","three_freqs","index1","index2","index3","index4"};
+  pyref keys = PyDict_Keys(dic);
+  if (!convertible_from_python<std::vector<std::string>>(keys, true)) {
+   fs << "\nThe dict keys are not strings";
+   goto _error;
+  }
+  ks = convert_from_python<std::vector<std::string>>(keys);
+  for (auto & k : ks)
+   if (std::find(all_keys.begin(), all_keys.end(), k) == all_keys.end())
+    fs << "\n"<< ++err << " The parameter '" << k << "' is not recognized.";
+#endif
+
+  _check_mandatory<gf_struct_t             >(dic, fs, err, "gf_struct"  , "gf_struct_t");
+  _check_mandatory<double                  >(dic, fs, err, "beta"       , "double");
+  _check_optional <pomerol2triqs::channel_t>(dic, fs, err, "channel"    , "pomerol2triqs::channel_t");
+  _check_mandatory<three_freqs_t           >(dic, fs, err, "three_freqs", "three_freqs_t");
+  _check_mandatory<indices_t               >(dic, fs, err, "index1"     , "indices_t");
+  _check_mandatory<indices_t               >(dic, fs, err, "index2"     , "indices_t");
+  _check_mandatory<indices_t               >(dic, fs, err, "index3"     , "indices_t");
+  _check_mandatory<indices_t               >(dic, fs, err, "index4"     , "indices_t");
+  if (err) goto _error;
+  return true;
+
+ _error:
+   fs2 << "\n---- There " << (err > 1 ? "are " : "is ") << err<< " error"<<(err >1 ?"s" : "")<< " in Python -> C++ transcription for the class g2_three_freqs_params_t\n" <<fs.str();
+   if (raise_exception) PyErr_SetString(PyExc_TypeError, fs2.str().c_str());
+  return false;
+ }
+};
+
 }}
\ No newline at end of file
diff --git a/python/pomerol2triqs_desc.py b/python/pomerol2triqs_desc.py
index 511deff..914eeb4 100644
--- a/python/pomerol2triqs_desc.py
+++ b/python/pomerol2triqs_desc.py
@@ -68,7 +68,10 @@
              doc = r"""Retarded Green's function on real energy axis""")
 
 c.add_method("""triqs::arrays::array<std::complex<double>, 3> G2_iw (**pomerol2triqs::g2_iw_inu_inup_params_t)""",
-             doc = r"""Two-particle Green's function, Matsubara frequencies""")
+             doc = r"""Two-particle Green's function. Specify frequency cutoff, n_b and n_f.""")
+
+c.add_method("""std::vector<std::complex<double> > G2_iw_three_freqs (**pomerol2triqs::g2_three_freqs_params_t)""",
+             doc = r"""Two-particle Green's function. Specify three frequencies (wb, wf1, wf2).""")
 
 module.add_class(c)
 
diff --git a/python/pomerol2triqs_parameters.rst b/python/pomerol2triqs_parameters.rst
index be8cd2e..6dddaaf 100644
--- a/python/pomerol2triqs_parameters.rst
+++ b/python/pomerol2triqs_parameters.rst
@@ -7,9 +7,31 @@
 +----------------+--------------------------+---------+----------------------------------------------------------------------+
 | channel        | pomerol2triqs::channel_t | PH      | Channel in which Matsubara frequency representation is defined.      |
 +----------------+--------------------------+---------+----------------------------------------------------------------------+
-| n_b            | int                      | --      | Number of bosonic Matsubara frequencies.                             |
+| n_b            | int                      | --      | Number of bosonic and fermionic Matsubara frequencies.               |
 +----------------+--------------------------+---------+----------------------------------------------------------------------+
-| n_f            | int                      | --      | Number of fermionic Matsubara frequencies.                           |
+| n_f            | int                      | --      | Number of bosonic and fermionic Matsubara frequencies.               |
++----------------+--------------------------+---------+----------------------------------------------------------------------+
+| index1         | indices_t                | --      | indices of operators in TRIQS convention: (block_name, inner_index)  |
++----------------+--------------------------+---------+----------------------------------------------------------------------+
+| index2         | indices_t                | --      | indices of operators in TRIQS convention: (block_name, inner_index)  |
++----------------+--------------------------+---------+----------------------------------------------------------------------+
+| index3         | indices_t                | --      | indices of operators in TRIQS convention: (block_name, inner_index)  |
++----------------+--------------------------+---------+----------------------------------------------------------------------+
+| index4         | indices_t                | --      | indices of operators in TRIQS convention: (block_name, inner_index)  |
++----------------+--------------------------+---------+----------------------------------------------------------------------+
+
+
+
++----------------+--------------------------+---------+----------------------------------------------------------------------+
+| Parameter Name | Type                     | Default | Documentation                                                        |
++================+==========================+=========+======================================================================+
+| gf_struct      | gf_struct_t              | --      | Block structure of GF                                                |
++----------------+--------------------------+---------+----------------------------------------------------------------------+
+| beta           | double                   | --      | Inverse temperature                                                  |
++----------------+--------------------------+---------+----------------------------------------------------------------------+
+| channel        | pomerol2triqs::channel_t | PH      | Channel in which Matsubara frequency representation is defined.      |
++----------------+--------------------------+---------+----------------------------------------------------------------------+
+| three_freqs    | three_freqs_t            | --      | three frequencies (wb, wf1, wf2).                                    |
 +----------------+--------------------------+---------+----------------------------------------------------------------------+
 | index1         | indices_t                | --      | indices of operators in TRIQS convention: (block_name, inner_index)  |
 +----------------+--------------------------+---------+----------------------------------------------------------------------+