Absolute cross-sections for m -fold photoionization ( IMG [http://ej.iop.org/images/0004-637X/849/1/5/apjaa8fccieqn1.gif] $m=1,ldots,6$ ) of Fe + by a single photon were measured employing the photon--ion merged-beams setup PIPE at the PETRA III synchrotron light source, operated by DESY in Hamburg, Germany. Photon energies were in the range 680--920 eV, which covers the photoionization resonances associated with IMG [http://ej.iop.org/images/0004-637X/849/1/5/apjaa8fccieqn2.gif] $2p$ and IMG [http://ej.iop.org/images/0004-637X/849/1/5/apjaa8fccieqn3.gif] $2s$ excitation to higher atomic shells as well as the thresholds for IMG [http://ej.iop.org/images/0004-637X/849/1/5/apjaa8fccieqn4.gif] $2p$ and IMG [http://ej.iop.org/images/0004-637X/849/1/5/apjaa8fccieqn5.gif] $2s$ ionization. The corresponding resonance positions were measured with an uncertainty of textpm0.2 eV. The cross-section for Fe + photoabsorption is derived as the sum of the individually measured cross-sections for m -fold ionization. Calculations of the Fe + absorption cross-sections were carried out using two different theoretical approaches, Hartree--Fock including relativistic extensions and fully relativistic multiconfiguration Dirac--Fock. Apart from overall energy shifts of up to about 3 eV, the theoretical cross-sections are in good agreement with each other and with the experimental results. In addition, the complex de-excitation cascades after the creation of inner-shell holes in the Fe + ion were tracked on the atomic fine-structure level. The corresponding theoretical results for the product charge-state distributions are in much better agreement with the experimental data than previously published configuration-average results. The present experimental and theoretical results are valuable for opacity calculations and are expected to pave the way to a more accurate determination of the iron abundance in the interstellar medium.