This maps the command key to control while using RDP

karabiner_cmd_to_ctrl.json

{
  "title": "Remote Desktop",
  "rules": [
    {
      "description": "Swap command and control",
      "manipulators": [
        {
          "type": "basic",
          "from": {
            "key_code": "left_control",
            "modifiers": {
              "optional": [
                "any"
              ]
            }
          },
          "to": [
            {
              "key_code": "left_command"
            }
          ],
          "conditions": [
            {
              "type": "frontmost_application_if",
              "bundle_identifiers": [
                "com\\.microsoft\\.rdc\\.mac"
              ]
            }
          ]
        },
        {
          "type": "basic",
          "from": {
            "key_code": "left_command",
            "modifiers": {
              "optional": [
                "any"
              ]
            }
          },
          "to": [
            {
              "key_code": "left_control"
            }
          ],
          "conditions": [
            {
              "type": "frontmost_application_if",
              "bundle_identifiers": [
                "com\\.microsoft\\.rdc\\.mac"
              ]
            }
          ]
        },
        {
          "type": "basic",
          "from": {
            "key_code": "right_control",
            "modifiers": {
              "optional": [
                "any"
              ]
            }
          },
          "to": [
            {
              "key_code": "right_command"
            }
          ],
          "conditions": [
            {
              "type": "frontmost_application_if",
              "bundle_identifiers": [
                "com\\.microsoft\\.rdc\\.mac"
              ]
            }
          ]
        },
        {
          "type": "basic",
          "from": {
            "key_code": "right_command",
            "modifiers": {
              "optional": [
                "any"
              ]
            }
          },
          "to": [
            {
              "key_code": "right_control"
            }
          ],
          "conditions": [
            {
              "type": "frontmost_application_if",
              "bundle_identifiers": [
                "com\\.microsoft\\.rdc\\.mac"
              ]
            }
          ]
        }
      ]
    }
  ]
}