Google Ads Agency: 5 Criteria forChoosing One and Doubling ROI in 2026

What is a Google Ads agency?

A Google Ads agency specialises in creating, managing and optimising paid advertising campaigns on Google. It runs Search, Shopping, Display and Performance Max ads to maximise return on advertising spend, with measurable results from the first few weeks.

Google holds 93% of the French search market (source: Statista, 2025). Millions of commercial searches take place every day without the relevant businesses appearing. A Google Ads agency closes this gap by putting you in front of customers at the moment they search for what you sell. According to Google (2024), advertisers generate an average €8 in revenue for every euro invested in properly structured and tracked campaigns.

Why use a Google Ads agency instead of managing campaigns in-house?

Google Ads is powerful but complex. Poorly configured campaigns burn budget without delivering results. A WordStream study (2024) found that 76% of self-managed accounts miss their conversion targets because their structure is unsuitable. Common mistakes include overly broad keywords, no negative keywords, unoptimised landing pages and unreliable conversion tracking.

A Google Ads agency combines keyword strategy, ad creation, bid optimisation, conversion tracking and data analysis. According to HubSpot (2024), certified experts generate three times more qualified leads than self-managed accounts on the same budget. Delegating also frees an SME to focus on its core business, a resource as valuable as the advertising budget itself.

Campaign types managed by a Google Ads agency

A capable agency goes beyond search. It uses every suitable format for lead generation, e-commerce sales, brand awareness or remarketing. Each campaign type addresses a different purchasing intent, and combining them strategically maximises presence throughout the customer journey (source: Google, 2024). Google's SERP also includes video results, so advanced agencies incorporate YouTube Ads into a coherent cross-channel strategy.

How to choose a Google Ads agency in 2026: five decisive criteria

Agencies are not equal. The cost-per-lead gap between generalist agencies treating Google Ads as an add-on and specialist paid-search agencies can reach 300% (source: WordStream, 2024). These criteria identify agencies capable of generating genuine ROI rather than clicks without conversions.

Google Ads agency budgets and fees in 2026

French agency management typically costs €400–€2,000 a month excluding media spend. Most charge 15% to 20% of managed spend or a fixed monthly fee. The recommended minimum media budget for profitable campaigns is €1,000–€1,500 a month. Below this, Google's Smart Bidding lacks conversion data. An SME investing €2,000 in advertising and €800 in fees can target ROAS of 4 to 6 when campaigns and landing pages are well structured (source: Google, 2024).

Beware very low fees: at €200 a month, an agency cannot devote more than two hours to an account. Search, Shopping and Remarketing require at least eight to 15 hours monthly. Your landing-page conversion rate is as important as spend: optimisation can halve CPA without increasing budget.

Google Ads agency vs freelancer vs in-house: which suits an SME?

Each of the three options has advantages depending on size, budget and advertising maturity. According to Forrester (2024), 58% of French SMEs with fewer than 50 employees use an external agency for paid search, versus 23% in-house and 19% using a freelancer. A freelancer's principal limitation is reliance on one person, with continuity lost through absence or departure; their advantage is fees often 30% to 40% below an agency. Our guide to SME SEO in 2026 explains how SEO and Google Ads complement one another.

Two practical SME cases: measured Google Ads agency results

Abstract figures tell only half the story. These two real examples show what a capable Google Ads agency can achieve for a French SME, with documented results and realistic timescales.

Case 1: HR consultancy, 15 employees, Paris. A €2,500 monthly budget had been managed in-house for 18 months, with €140 CPA and 1.8% conversion. After an agency audit and restructure, 312 negative keywords and three offer-specific landing pages, CPA fell to €52 and conversion reached 4.7% within 90 days. Monthly saving: €1,200 for the same lead volume.

Case 2: fashion retailer, eight employees, Lyon. A €4,000 monthly Google Shopping budget used automated Smart Shopping, with 2.1 ROAS. After migration to Performance Max, an optimised product feed, margin-based segmentation and out-of-stock exclusions, ROAS reached 4.8 within four months. Annual gain: €128,000 in advertising revenue at constant spend.

The La Refonte method for Google Ads campaigns

La Refonte uses a four-phase method tested across more than 40 SME accounts. Phase 1: complete audit of an existing account or sector competitors, over two weeks. Phase 2: campaign structure, detailed keyword research and conversion tracking, over one week. Phase 3: launch and learning over 30 to 45 days, allowing Google Ads to gather real conversion data before bid optimisation. Phase 4: continuous monthly optimisation with detailed reporting.

You retain full account access at all times. There is no restrictive annual contract: the engagement renews monthly. Reports cover CPA, ROAS, top keywords and completed actions. For clients whose site is already optimised for conversion, essential for profitable Google Ads, launch is 30% shorter.