Juan Lomas appeals the sentence imposed following his guilty-plea conviction for two counts of unlawful transportation of illegal aliens in violation of 8 U.S.C. § 1324. Lomas argues that the district court erred in imposing his sentence under the then mandatory United States Sentencing Guidelines held unconstitutional in United States v. Booker, 543 U.S. 220, 125 S.Ct. 738, 160 L.Ed.2d 621 (2005). Lomas specifically objected to the sentence based on the then pending Booker and Fanfan cases. The Government concedes that Lo-mas’s objection based on Blakely v. Washington, 542 U.S. 296, 124 S.Ct. 2531, 159 L.Ed.2d 403 (2004), at sentencing was sufficient to preserve his Fanfan claim. See United States v. Walters, 418 F.3d 461, 463 (5th Cir. 2005)(discussing difference between Booker error and Fanfan error). We review preserved Fanfan claims for harmless error. United States v. Mares, 402 F.3d 511, 520 n. 9 (5th Cir.), cert. denied, — U.S. -, 126 S.Ct. 43, 163 L.Ed.2d 76 (2005). The Government must prove beyond a reasonable doubt that the outcome of the district court proceedings was not affected by the application of the mandatory Guidelines.

The Government has not demonstrated that the Fanfan error was harmless beyond a reasonable doubt. The district court expressly declined to say what the sentence would be if Booker and Fanfan were decided favorably to Lomas. The district court did not make any comments indicating whether it would have imposed the same sentence under an advisory guidelines system.

The case is REMANDED for reconsideration by the district court and to resentence Lomas if appropriate.