indicatif is "approximate" in a context like this.

TEG / taux effectif global usually translates as APR / "annual percentage rate": it is used in the same "consumer protection" context.

Strictly speaking TEG should not be translated as "annual" anything as the frequency doesn't appear in the term. The more common and more recent term is TAEG, taux effectif annuel global, which is more helpful.

Here, the use of périodique indicates that frequencies other than but also including annual are involved.

I find this in a "Google Book" called "Calculs financiers et évaluations mathématiques en gestion de patrimoine": "Une fois le T.E.G. périodique trouvé on passe au T.E.G. annuel en multilpliant le T.E.G. périodique par le nombre de périodes contenues dans une année".

Dividing 2.45 by 0.20 gives 12.25. Dividing 2.45 by 12 gives 0.2041667.

They would appear to be rounding to the second decimal place. This is thus an approximate monthly percentage rate.

So why would they use périodique rather than mensuel? It appears that both this FR term and the translation I have given in EN are commonly used by professionals in the finance sector. I wonder whether the frequency of this "period" is mentioned somewhere else in your document.

Just googling a bit I found this, about US legislators being unhappy with the EN phrase being permitted when communicating with consumers:
"Representative Patman and ten other Congressmen, issued a Supplemental View which set forth their displeasure with the committee's amendment to the proposed bill which permitted certain open end creditors to express their charges to consumers in periodic percentage rate basis rather than on an annual basis ..."

Maybe they take a different view in France. Or maybe your document is quite an old one: as I say, TAEG is now more common.

As for global: this is the French being more precise that the UK legislator. The French term explicitly reflects the fact that to calculate the lending figure various charges (not just the interest) must be taken into account, such as administrative costs, commissions, insurance, etc. I don't know whether the UK consumer legislation also requires this when calculating APR, but I believe so.