diff --git a/include/bbp/sonata/config.h b/include/bbp/sonata/config.h
index 3edd6968..c223af9b 100644
--- a/include/bbp/sonata/config.h
+++ b/include/bbp/sonata/config.h
@@ -186,9 +186,9 @@ class SONATA_API SimulationConfig
      */
     struct Run {
         /// Biological simulation end time in milliseconds
-        float tstop{};
+        double tstop{};
         /// Integration step duration in milliseconds
-        float dt{};
+        double dt{};
     };
     /**
      * Parameters to override simulator output for spike reports
@@ -208,11 +208,11 @@ class SONATA_API SimulationConfig
         /// Report type. Possible values: "compartment", "summation", "synapse"
         std::string type;
         /// Interval between reporting steps in milliseconds
-        float dt{};
+        double dt{};
         /// Time to step reporting in milliseconds
-        float startTime{};
+        double startTime{};
         /// Time to stop reporting in milliseconds
-        float endTime{};
+        double endTime{};
         /// Report filename. Default is "<report name>_SONATA.h5"
         std::string fileName;
     };
@@ -265,6 +265,8 @@ class SONATA_API SimulationConfig
      */
     const Report& getReport(const std::string& name) const;
 
+    const std::string& getNetwork() const noexcept;
+
   private:
     // JSON string
     const std::string _jsonContent;
@@ -277,6 +279,8 @@ class SONATA_API SimulationConfig
     Output _output;
     // List of reports
     std::unordered_map<std::string, Report> _reports;
+    // Path of circuit config file for the simulation
+    std::string _network;
 
     class Parser;
     friend class Parser;
diff --git a/python/bindings.cpp b/python/bindings.cpp
index ed07225f..fcba57c6 100644
--- a/python/bindings.cpp
+++ b/python/bindings.cpp
@@ -561,6 +561,7 @@ PYBIND11_MODULE(_libsonata, m) {
         .def_property_readonly("json", &SimulationConfig::getJSON)
         .def_property_readonly("run", &SimulationConfig::getRun)
         .def_property_readonly("output", &SimulationConfig::getOutput)
+        .def_property_readonly("network", &SimulationConfig::getNetwork)
         .def("report", &SimulationConfig::getReport, "name"_a);
 
     bindPopulationClass<EdgePopulation>(
diff --git a/python/tests/test.py b/python/tests/test.py
index d5662a5a..4b178d14 100644
--- a/python/tests/test.py
+++ b/python/tests/test.py
@@ -585,7 +585,7 @@ def test_basic(self):
         self.assertEqual(self.config.base_path, os.path.abspath(os.path.join(PATH, 'config')))
 
         self.assertEqual(self.config.run.tstop, 1000)
-        self.assertTrue(abs(self.config.run.dt - 0.025) < 0.01)
+        self.assertEqual(self.config.run.dt, 0.025)
 
         self.assertEqual(self.config.output.output_dir,
                          os.path.abspath(os.path.join(PATH, 'config/output')))
@@ -593,12 +593,15 @@ def test_basic(self):
 
         self.assertEqual(self.config.report('soma').cells, 'Mosaic')
         self.assertEqual(self.config.report('soma').type, 'compartment')
-        self.assertTrue(abs(self.config.report('compartment').dt - 0.1) < 0.01)
+        self.assertEqual(self.config.report('compartment').dt, 0.1)
         self.assertEqual(self.config.report('axonal_comp_centers').start_time, 0)
         self.assertEqual(self.config.report('axonal_comp_centers').file_name,
                          os.path.abspath(os.path.join(PATH, 'config/axon_centers.h5')))
         self.assertEqual(self.config.report('cell_imembrane').end_time, 500)
 
+        self.assertEqual(self.config.network,
+                         os.path.abspath(os.path.join(PATH, 'config/circuit_config.json')))
+
     def test_json(self):
         temp_config = json.loads(self.config.json)
         self.assertEqual(temp_config['run']['tstop'], 1000)
diff --git a/src/config.cpp b/src/config.cpp
index e950e013..e50fa028 100644
--- a/src/config.cpp
+++ b/src/config.cpp
@@ -103,7 +103,7 @@ using Variables = std::map<std::string, std::string>;
 Variables readVariables(const nlohmann::json& json) {
     Variables variables;
 
-    if (json.find("networks") == json.end() || json.find("manifest") == json.end()) {
+    if (json.find("manifest") == json.end()) {
         return variables;
     }
 
@@ -482,8 +482,12 @@ class SimulationConfig::Parser
 {
   public:
     Parser(const std::string& content, const std::string& basePath)
-        : _basePath(fs::absolute(fs::path(basePath)).lexically_normal())
-        , _json(nlohmann::json::parse(content)) {}
+        : _basePath(fs::absolute(fs::path(basePath)).lexically_normal()) {
+        // Parse manifest section and expand JSON string
+        const auto rawJson = nlohmann::json::parse(content);
+        const auto vars = replaceVariables(readVariables(rawJson));
+        _json = expandVariables(rawJson, vars);
+    }
 
     template <typename Iterator, typename Type, typename SectionName>
     void parseMandatory(const Iterator& it,
@@ -560,9 +564,14 @@ class SimulationConfig::Parser
         return result;
     }
 
+    const std::string parseNetwork() const {
+        auto val = _json.find("network") != _json.end() ? _json["network"] : "circuit_config.json";
+        return toAbsolute(_basePath, val);
+    }
+
   private:
     const fs::path _basePath;
-    const nlohmann::json _json;
+    nlohmann::json _json;
 };
 
 SimulationConfig::SimulationConfig(const std::string& content, const std::string& basePath)
@@ -572,6 +581,7 @@ SimulationConfig::SimulationConfig(const std::string& content, const std::string
     _run = parser.parseRun();
     _output = parser.parseOutput();
     _reports = parser.parseReports();
+    _network = parser.parseNetwork();
 }
 
 SimulationConfig SimulationConfig::fromFile(const std::string& path) {
@@ -594,6 +604,10 @@ const SimulationConfig::Output& SimulationConfig::getOutput() const noexcept {
     return _output;
 }
 
+const std::string& SimulationConfig::getNetwork() const noexcept {
+    return _network;
+}
+
 const SimulationConfig::Report& SimulationConfig::getReport(const std::string& name) const {
     const auto it = _reports.find(name);
     if (it == _reports.end())
diff --git a/tests/data/config/simulation_config.json b/tests/data/config/simulation_config.json
index e32efc5e..1172131c 100644
--- a/tests/data/config/simulation_config.json
+++ b/tests/data/config/simulation_config.json
@@ -1,5 +1,8 @@
 {
-    "run": {
+     "manifest": {
+         "$OUTPUT_DIR": "."
+     },
+     "run": {
          "tstop": 1000,
          "dt": 0.025,
          "random_seed": 201506,
@@ -8,7 +11,7 @@
          "forward_skip": 500
     },
     "output": {
-         "output_dir": "output",
+         "output_dir": "$OUTPUT_DIR/output",
          "spikes_file": "out.h5"
     },
     "reports": {
diff --git a/tests/test_config.cpp b/tests/test_config.cpp
index b032066c..74e7248d 100644
--- a/tests/test_config.cpp
+++ b/tests/test_config.cpp
@@ -296,8 +296,8 @@ TEST_CASE("SimulationConfig") {
         const auto config = SimulationConfig::fromFile("./data/config/simulation_config.json");
         CHECK_NOTHROW(config.getRun());
         using Catch::Matchers::WithinULP;
-        REQUIRE_THAT(config.getRun().tstop, WithinULP(1000.f, 1));
-        REQUIRE_THAT(config.getRun().dt, WithinULP(0.025f, 1));
+        CHECK(config.getRun().tstop == 1000);
+        CHECK(config.getRun().dt == 0.025);
 
         namespace fs = ghc::filesystem;
         const auto basePath = fs::absolute(
@@ -312,17 +312,36 @@ TEST_CASE("SimulationConfig") {
 
         CHECK(config.getReport("soma").cells == "Mosaic");
         CHECK(config.getReport("soma").type == "compartment");
-        CHECK(config.getReport("compartment").dt == 0.1f);
-        CHECK(config.getReport("axonal_comp_centers").startTime == 0.f);
+        CHECK(config.getReport("compartment").dt == 0.1);
+        CHECK(config.getReport("axonal_comp_centers").startTime == 0.);
         const auto axonalFilePath = fs::absolute(basePath / fs::path("axon_centers.h5"));
         CHECK(config.getReport("axonal_comp_centers").fileName ==
               axonalFilePath.lexically_normal());
-        CHECK(config.getReport("cell_imembrane").endTime == 500.f);
+        CHECK(config.getReport("cell_imembrane").endTime == 500.);
 
         CHECK_NOTHROW(nlohmann::json::parse(config.getJSON()));
         CHECK(config.getBasePath() == basePath.lexically_normal());
-    }
 
+        const auto network = fs::absolute(basePath / fs::path("circuit_config.json"));
+        CHECK(config.getNetwork() == network.lexically_normal());
+    }
+    SECTION("manifest_network") {
+        auto contents = R"({
+          "manifest": {
+            "$CIRCUIT_DIR": "./circuit"
+          },
+          "network": "$CIRCUIT_DIR/circuit_config.json",
+          "run": {
+            "dt": 0.05,
+            "tstop": 1000
+          }
+        })";
+        namespace fs = ghc::filesystem;
+        const auto basePath = fs::absolute(fs::path("./").parent_path());
+        const auto config = SimulationConfig(contents, basePath);
+        const auto network = fs::absolute(basePath / "circuit" / fs::path("circuit_config.json"));
+        CHECK(config.getNetwork() == network.lexically_normal());
+    }
     SECTION("Exception") {
         {  // No run section
             auto contents = R"({})";