“In all preventive retention cases, the VAT administration must undertake in the event of the taxable person being ultimately successful in the main action concerning the retention, to pay interest on the sum retained from the moment when, in accordance with the normal deduction rules applied in that member state in the implementation of the Sixth Directive, the sum would have been paid to that taxable person.”
“62. Fifth, the plaintiffs state that, under Belgian law, in the event of release of the retained VAT balances, interest is not payable by the treasury unless the sums retained have not been duly returned by 31 March of the year following that in which the refundable balances came into being and unless the amount refundable is at least BF 10,000, the last VAT return for the calendar year in which the VAT credit arose was signed at the place on the form indicated for that purpose and all the VAT returns have been filed within the prescribed time limits. 63. In that regard, it must be observed that it is not necessary, in order to attain the objective pursued by legislation such as that at issue in the main proceedings, namely to ensure recovery of the amounts due, for interest to be calculated from a date other than that on which the retained VAT balance would normally have been paid under the Sixth Directive, and therefore that the principle of proportionality precludes the application of such legislation. The same applies to the other conditions mentioned above: in particular, lateness in filing returns can be penalised in a manner unconnected with the retention procedure and without affecting the right to refund of the VAT balance. 64. The answer to be given must therefore be that it is for the national court to examine whether or not the measures in question and the manner in which they are applied by the competent administrative authority are proportionate. In the context of that examination, if the national provisions or a particular construction of them would constitute a bar to effective judicial review, in particular review of the urgency and necessity of retaining the refundable VAT balance, and would prevent the taxable person from applying to a court for replacement of the retention by another guarantee sufficient to protect the interest of the treasury but less onerous for the taxable person, or would prevent an order from being made, at any stage of the procedure, for the total or partial lifting of the retention, the national court should disapply those provisions or refrain from placing such a construction on them. Moreover in the event of the retention being lifted, calculation of the interest payable by the treasury which did not take as its starting point the date on which the VAT balance in question would have had to be repaid in the normal course of events would be contrary to the principle of proportionality.”