  Tremendous efforts have been devoted to the search for exotic topological
states, which usually exist at an interface between lattices with differing
topological invariants according to the bulk-edge correspondence. Here, we show
a new finding of topological states localized at the interface between two
gauge-shifted Floquet photonic lattices, despite the same topological order
across the entire structure. The quasienergy band structures reveal that these
new interface modes belong to the Floquet {\pi} modes, which are further found
to enable a robust one-way propagation thanks to the flexible control of the
Floquet gauge. The intriguing propagations of these {\pi}-interface modes are
experimentally verified in a silicon waveguides platform at near-infrared
wavelengths, which show both broad working bandwidth and high tolerance to the
structural fluctuations. Our approach provides a new route for light
manipulations with robust behaviours in Floquet engineering and beyond.
