Martin Vega-Perez (Vega) appeals his sentence following his guilty plea conviction for illegal reentry following deportation. He argues that his sentence is unconstitutional in light of United States v. Booker, 543 U.S. 220, 125 S.Ct. 738, 160 L.Ed.2d 621 (2005), because it was increased based upon facts which were not alleged in his indictment, proven to a jury beyond a reasonable doubt, or admitted by him at his guilty plea. He further contends that his sentence is unconstitutional because he was sentenced pursuant to the mandatory federal sentencing guideline system declared unconstitutional in Booker.

In the instant case, there was no Booker error or Sixth Amendment violation because the only enhancement to Vega’s sentence was due to his prior felony conviction. See Booker, 543 U.S. at 244, 125 S.Ct. 738. Nevertheless, the district court did err in sentencing Vega pursuant to a mandatory guidelines system. See United States v. Walters, 418 F.3d 461, 463 (5th Cir. 2005). The Government concedes that Vega preserved this error for appeal. The Government, however, has not shown beyond a reasonable doubt that the error was harmless. See Walters, 418 F.3d at 463; United States v. Woods, 440 F.3d 255, 258-261 (5th Cir. 2006). Accordingly, Vega’s sentence is vacated, and this case is remanded for resentencing.

CONVICTION AFFIRMED; SENTENCE VACATED; REMANDED FOR RESENTENCING.