diff --git a/modules/bim/lib/api/bim/utilities/path_helper.rb b/modules/bim/lib/api/bim/utilities/path_helper.rb
index 4bf70f85552..0344899dd24 100644
--- a/modules/bim/lib/api/bim/utilities/path_helper.rb
+++ b/modules/bim/lib/api/bim/utilities/path_helper.rb
@@ -51,20 +51,27 @@ module API
           end
 
           def project(identifier)
-            "#{root}projects/#{identifier}"
+            path_segments("projects", identifier)
           end
 
           def topics(project_identifier)
-            "#{project(project_identifier)}/topics"
+            path_segments("projects", project_identifier, "topics")
           end
 
           def topic(project_identifier, uuid)
-            "#{topics(project_identifier)}/#{uuid}"
+            path_segments("projects", project_identifier, "topics", uuid)
           end
 
           def viewpoint(project_identifier, topic_uuid, viewpoint_topic)
-            "#{topic(project_identifier, topic_uuid)}/viewpoints/#{viewpoint_topic}"
+            path_segments("projects", project_identifier, "topics", topic_uuid, "viewpoints", viewpoint_topic)
           end
+
+          def path_segments(*segments)
+            subpath = segments.map { |segment| ::ERB::Util.url_encode(segment.to_s) }.join("/")
+            "#{root}#{subpath}"
+          end
+
+          private_class_method :path_segments
         end
 
         def bcf_v2_1_paths
diff --git a/modules/bim/spec/lib/api/bim/utilities/path_helper_spec.rb b/modules/bim/spec/lib/api/bim/utilities/path_helper_spec.rb
new file mode 100644
index 00000000000..75fb6885f16
--- /dev/null
+++ b/modules/bim/spec/lib/api/bim/utilities/path_helper_spec.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+#-- copyright
+# OpenProject is an open source project management software.
+# Copyright (C) the OpenProject GmbH
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License version 3.
+#
+# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
+# Copyright (C) 2006-2013 Jean-Philippe Lang
+# Copyright (C) 2010-2013 the ChiliProject Team
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+#
+# See COPYRIGHT and LICENSE files for more details.
+#++
+require "spec_helper"
+
+RSpec.describe API::Bim::Utilities::PathHelper::BCF2_1Path do # rubocop:disable RSpec/SpecFilePathFormat
+  before do
+    allow(described_class)
+      .to receive(:root_path)
+      .and_return("/openproject/")
+  end
+
+  describe ".project" do
+    it "escapes slash characters in project identifiers" do
+      expect(described_class.project("project/with/path"))
+        .to eq("/openproject/api/bcf/2.1/projects/project%2Fwith%2Fpath")
+    end
+  end
+
+  describe ".topic" do
+    it "escapes topic UUIDs so they stay a single path segment" do
+      expect(described_class.topic("my/project", "topic/with/path"))
+        .to eq("/openproject/api/bcf/2.1/projects/my%2Fproject/topics/topic%2Fwith%2Fpath")
+    end
+  end
+end