Not all of the apps will work on the smaller screened device, and some apps require Android 4.3 which as you know, has not yet officially been released for the phone. Some of the apps, like Samsung Wallet and Samsung's secure business app Samsung KNOX, will be coming to the Samsung Galaxy S4 with the Android 4.3 update. Apps available include MyFiles, Galaxy Note 3 MMS and the Galaxy Camera for the Galaxy Note 3.
If you have some interest in loading Galaxy Note 3 apps on your Galaxy S4 handset, click on the sourcelink below.
source: XDA via RedmondPie