FortiSwitch integrate with FortiGate

have a look at the documentation about this:

https://help.fortinet.com/fos50hlp/56/Content/FortiOS/fortigate-managing-fortiswitch/Introduction.htm

 

and for port isolation look at

Enabling and disabling switch-controller access VLANs through FortiGateAccess VLANs are VLANs that aggregate client traffic solely to the FortiGate. This prevents direct client-to-client traffic visibility at the layer-2 VLAN layer. Clients can only communicate with the FortiGate. After the client traffic reaches the FortiGate, the FortiGate can then determine whether to allow various levels of access to the client by shifting the client's network VLAN as appropriate.

Use enable to allow traffic only to and from the FortiGate and to block FortiSwitch port-to-port traffic on the specified VLAN. Use disable to allow normal traffic on the specified VLAN.

config system interface

edit <VLAN name>

set switch-controller-access-vlan {enable | disable}

next

end